Support 'section' attribute #8

4ntoine · 2014-11-26T21:02:08Z

How to add support:
http://clang.llvm.org/docs/InternalsManual.html#id46

Certain ARM instructions accept 32-bit immediate operands encoded as a 8-bit integer value (0-255) and a 4-bit rotation (0-30, even). Current ARM assembly syntax support in LLVM allows the decoded (32-bit) immediate to be specified as a single immediate operand for such instructions: mov r0, #4278190080 The ARMARM defines an extended assembly syntax allowing the encoding to be made more explicit, as in: mov r0, #255, #8 ; (same 32-bit value as above) The behaviour of the two instructions can be different w.r.t flags, which is documented under "Modified immediate constants" in ARMARM. This patch enables support for this extended syntax at the MC layer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223113 91177308-0d34-0410-b5e6-96231b3b80d8

This frequently leads to cases like: ldr xD, [xN, :lo12:var] add xA, xN, :lo12:var ldr xD, [xA, #8] where the ADD would have been needed anyway, and the two distinct addressing modes can prevent the formation of an ldp. Because of how we handle ADRP (aggressively forming an ADRP/ADD pseudo-inst at ISel time), this pattern also results in duplicated ADRP instructions (one on its own to cover the ldr, and one combined with the add). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223172 91177308-0d34-0410-b5e6-96231b3b80d8

No functional changes. Got myself bitten in r223113 when adding support for modified immediate syntax (regressions reported by [email protected], fixes in r223366 and r223381). Our assembler tests did not cover serveral different syntax variants. This patch expands the test coverage to check for the following cases: 1. Modified immediate operands may be expressed with expressions, as in #(4 * 2) instead of #8. 2. Modified immediate operands may be _optionally_ prefixed by a '#' symbol or a '$' symbol. 3. Certain instructions (e.g. ADD) support single input register variants; [ADD r0, #mod_imm] is same as [ADD r0, r0, #mod_imm]. 4. Certain instructions have aliases which convert plain immediates to modified immediates. For an example, [ADD r0, -10] is not valid because -10 (in two's complement) cannot be encoded as a modified immediate, but ARMInstrInfo.td defines an alias which can transform this into a [SUB r0, 10]. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223475 91177308-0d34-0410-b5e6-96231b3b80d8

…ndling into vector of loads, and vectorizes it. Test case : float hadd(float* a) { return (a[0] + a[1]) + (a[2] + a[3]); } AArch64 assembly before patch : ldp s0, s1, [x0] ldp s2, s3, [x0, #8] fadd s0, s0, s1 fadd s1, s2, s3 fadd s0, s0, s1 ret AArch64 assembly after patch : ldp d0, d1, [x0] fadd v0.2s, v0.2s, v1.2s faddp s0, v0.2s ret Reviewed Link : http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20141208/248531.html git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224119 91177308-0d34-0410-b5e6-96231b3b80d8

dylanmckay · 2014-12-30T08:41:18Z

I have a very, very strong feeling that this will automatically be handled by the LLVM ELF implementation, but I will not close this issue until I double check.

…airs. Store instructions do not modify register values and therefore it's safe to form a store pair even if the source register has been read in between the two store instructions. Previously, the read of w1 (see below) prevented the formation of a stp. str w0, [x2] ldr w8, [x2, #8] add w0, w8, w1 str w1, [x2, #4] ret We now generate the following code. stp w0, w1, [x2] ldr w8, [x2, #8] add w0, w8, w1 ret All correctness tests with -Ofast on A57 with Spec200x and EEMBC pass. Performance results for SPEC2K were within noise. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239432 91177308-0d34-0410-b5e6-96231b3b80d8

These are really immediate DUPs, and suffer from the same problem with long instructions with a high/2 variant (e.g. smull). By extending a MOVI (or DUP, before this patch), we can avoid an ext on the other operand of the long instruction, e.g. turning: ext.16b v0, v0, v0, #8 movi.4h v1, #0x53 smull.4s v0, v0, v1 into: movi.8h v1, #0x53 smull2.4s v0, v0, v1 While there, add a now-necessary combine to fold (VT NVCAST (VT x)). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239799 91177308-0d34-0410-b5e6-96231b3b80d8

In vectorized add reduction code, the final "reduce" step is sub-optimal. This change wll combine : ext v1.16b, v0.16b, v0.16b, #8 add v0.4s, v1.4s, v0.4s dup v1.4s, v0.s[1] add v0.4s, v1.4s, v0.4s into addv s0, v0.4s PR21371 http://reviews.llvm.org/D12325 Patch by Jun Bum Lim <[email protected]>! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246790 91177308-0d34-0410-b5e6-96231b3b80d8

@t

The current behavior is incorrect, as the two CCs returned by changeFPCCToAArch64CC, intended to be OR'ed, are instead used in an AND ccmp chain. Consider: define i32 @t(float %a, float %b, float %c, float %d, i32 %e, i32 %f) { %cc1 = fcmp one float %a, %b %cc2 = fcmp olt float %c, %d %and = and i1 %cc1, %cc2 %r = select i1 %and, i32 %e, i32 %f ret i32 %r } Assuming (%a < %b) and (%c < %d); we used to do: fcmp s0, s1 # nzcv <- 1000 orr w8, wzr, #0x1 # w8 <- 1 csel w9, w8, wzr, mi # w9 <- 1 csel w8, w8, w9, gt # w8 <- 1 fcmp s2, s3 # nzcv <- 1000 cset w9, mi # w9 <- 1 tst w8, w9 # (w8 & w9) == 1, so: nzcv <- 0000 csel w0, w0, w1, ne # w0 <- w0 We now do: fcmp s2, s3 # nzcv <- 1000 fccmp s0, s1, #0, mi # mi, so: nzcv <- 1000 fccmp s0, s1, #8, le # !le, so: nzcv <- 1000 csel w0, w0, w1, pl # !pl, so: w0 <- w1 In other words, we transformed: (c < d) && ((a < b) || (a > b)) into: (c < d) && (a u>= b) && (a u<= b) whereas, per De Morgan's, we wanted: (c < d) && !((a u>= b) && (a u<= b)) Note that this problem doesn't occur in the test-suite. changeFPCCToAArch64CC produces disjunct CCs; here, one -> mi/gt. We can't represent that in the fccmp chain; it can't express arbitrary OR sequences, as one comment explains: In general we can create code for arbitrary "... (and (and A B) C)" sequences. We can also implement some "or" expressions, because "(or A B)" is equivalent to "not (and (not A) (not B))" and we can implement some negation operations. [...] However there is no way to negate the result of a partial sequence. Instead, introduce changeFPCCToANDAArch64CC, which produces the conjunct cond codes: - (a one b) == ((a olt b) || (a ogt b)) == ((a ord b) && (a une b)) - (a ueq b) == ((a uno b) || (a oeq b)) == ((a ule b) && (a uge b)) Note that, at first, one might think that, when PushNegate is true, we should use the disjunct CCs, in effect doing: (a || b) = !(!a && !(b)) = !(!a && !(b1 || b2)) <- changeFPCCToAArch64CC(b, b1, b2) = !(!a && !b1 && !b2) However, we can take advantage of the fact that the CC is already negated, which lets us avoid special-casing PushNegate and doing the simpler to reason about: (a || b) = !(!a && (!b)) = !(!a && (b1 && b2)) <- changeFPCCToANDAArch64CC(!b, b1, b2) = !(!a && b1 && b2) This makes both emitConditionalCompare cases behave identically, and produces correct ccmp sequences for the 2-CC fcmps. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258533 91177308-0d34-0410-b5e6-96231b3b80d8

Summary: This change merges adjacent 32 bit zero stores into a 64 bit zero store. e.g., str wzr, [x0] str wzr, [x0, #4] becomes str xzr, [x0] Therefore, four adjacent 32 bit zero stores will be a single stp. e.g., str wzr, [x0] str wzr, [x0, #4] str wzr, [x0, #8] str wzr, [x0, #12] becomes stp xzr, xzr, [x0] Reviewers: mcrosier, jmolloy, gberry, t.p.northover Subscribers: aemerson, rengolin, mcrosier, llvm-commits Differential Revision: http://reviews.llvm.org/D16933 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260682 91177308-0d34-0410-b5e6-96231b3b80d8

@inc

Summary: For instance, compiling the below results in a panic: ``` llc: ../lib/CodeGen/InlineSpiller.cpp:1140: bool (anonymous namespace)::InlineSpiller::foldMemoryOperand(ArrayRef<std::pair<MachineInstr *, unsigned int> >, llvm::MachineInstr *): Assertion `MO->isDead() && "Cannot fold physreg def"' failed. #0 0x00007f50fbcf353e llvm::sys::PrintStackTrace(llvm::raw_ostream&) /home/h/3rd/llvm/build/../lib/Support/Unix/Signals.inc:321:15 #1 0x00007f50fbcf3929 PrintStackTraceSignalHandler(void*) /home/h/3rd/llvm/build/../lib/Support/Unix/Signals.inc:380:1 #2 0x00007f50fbcf22a3 llvm::sys::RunSignalHandlers() /home/h/3rd/llvm/build/../lib/Support/Signals.cpp:45:5 #3 0x00007f50fbcf3bb4 SignalHandler(int) /home/h/3rd/llvm/build/../lib/Support/Unix/Signals.inc:210:1 #4 0x00007f50fa87a180 (/lib/x86_64-linux-gnu/libc.so.6+0x35180) #5 0x00007f50fa87a107 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x35107) #6 0x00007f50fa87b4e8 abort (/lib/x86_64-linux-gnu/libc.so.6+0x364e8) #7 0x00007f50fa873226 (/lib/x86_64-linux-gnu/libc.so.6+0x2e226) #8 0x00007f50fa8732d2 (/lib/x86_64-linux-gnu/libc.so.6+0x2e2d2) #9 0x00007f50fddd9287 (anonymous namespace)::InlineSpiller::foldMemoryOperand(llvm::ArrayRef<std::pair<llvm::MachineInstr*, unsigned int> >, llvm::MachineInstr*) /home/h/3rd/llvm/build/../lib/CodeGen/InlineSpiller.cpp:1141:21 #10 0x00007f50fddd9ee9 (anonymous namespace)::InlineSpiller::spillAroundUses(unsigned int) /home/h/3rd/llvm/build/../lib/CodeGen/InlineSpiller.cpp:1286:9 #11 0x00007f50fddd388b (anonymous namespace)::InlineSpiller::spillAll() /home/h/3rd/llvm/build/../lib/CodeGen/InlineSpiller.cpp:1338:21 #12 0x00007f50fddd221d (anonymous namespace)::InlineSpiller::spill(llvm::LiveRangeEdit&) /home/h/3rd/llvm/build/../lib/CodeGen/InlineSpiller.cpp:1391:3 #13 0x00007f50fdfd921b (anonymous namespace)::RAGreedy::selectOrSplitImpl(llvm::LiveInterval&, llvm::SmallVectorImpl<unsigned int>&, llvm::SmallSet<unsigned int, 16u, std::less<unsigned int> >&, unsigned int) /home/h/3rd/llvm/build/../lib/CodeGen/RegAllocGreedy.cpp:2555:5 #14 0x00007f50fdfd647b (anonymous namespace)::RAGreedy::selectOrSplit(llvm::LiveInterval&, llvm::SmallVectorImpl<unsigned int>&) /home/h/3rd/llvm/build/../lib/CodeGen/RegAllocGreedy.cpp:2221:12 #15 0x00007f50fdfc89f9 llvm::RegAllocBase::allocatePhysRegs() /home/h/3rd/llvm/build/../lib/CodeGen/RegAllocBase.cpp:110:14 #16 0x00007f50fdfd6337 (anonymous namespace)::RAGreedy::runOnMachineFunction(llvm::MachineFunction&) /home/h/3rd/llvm/build/../lib/CodeGen/RegAllocGreedy.cpp:2611:3 #17 0x00007f50fded33ee llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /home/h/3rd/llvm/build/../lib/CodeGen/MachineFunctionPass.cpp:43:3 #18 0x00007f50fd6cdc6f llvm::FPPassManager::runOnFunction(llvm::Function&) /home/h/3rd/llvm/build/../lib/IR/LegacyPassManager.cpp:1550:23 #19 0x00007f50fd6cdf85 llvm::FPPassManager::runOnModule(llvm::Module&) /home/h/3rd/llvm/build/../lib/IR/LegacyPassManager.cpp:1571:16 #20 0x00007f50fd6ce71a (anonymous namespace)::MPPassManager::runOnModule(llvm::Module&) /home/h/3rd/llvm/build/../lib/IR/LegacyPassManager.cpp:1627:23 #21 0x00007f50fd6ce246 llvm::legacy::PassManagerImpl::run(llvm::Module&) /home/h/3rd/llvm/build/../lib/IR/LegacyPassManager.cpp:1730:16 #22 0x00007f50fd6cec31 llvm::legacy::PassManager::run(llvm::Module&) /home/h/3rd/llvm/build/../lib/IR/LegacyPassManager.cpp:1761:3 #23 0x0000000000415bdc compileModule(char**, llvm::LLVMContext&) /home/h/3rd/llvm/build/../tools/llc/llc.cpp:405:5 #24 0x0000000000414571 main /home/h/3rd/llvm/build/../tools/llc/llc.cpp:211:13 #25 0x00007f50fa866b45 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b45) #26 0x0000000000414296 _start (/home/h/3rd/llvm/build/bin/llc+0x414296) Stack dump: 0. Program arguments: ./bin/llc -mtriple msp430 loadstore.ll 1. Running pass 'Function Pass Manager' on module 'loadstore.ll'. 2. Running pass 'Greedy Register Allocator' on function '@inc' ``` Original IR: ```llvm %struct.VeryLarge = type { i8, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32 } ; Function Attrs: norecurse nounwind define void @inc(%struct.VeryLarge* noalias nocapture sret %agg.result, %struct.VeryLarge* byval align 1 %s) #0 { entry: %p0 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 0 %0 = load i8, i8* %p0, align 1, !tbaa !1 %p1 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 1 %1 = load i32, i32* %p1, align 1, !tbaa !6 %p2 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 2 %2 = load i32, i32* %p2, align 1, !tbaa !7 %p3 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 3 %3 = load i32, i32* %p3, align 1, !tbaa !8 %p4 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 4 %4 = load i32, i32* %p4, align 1, !tbaa !9 %p5 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 5 %5 = load i32, i32* %p5, align 1, !tbaa !10 %p6 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 6 %6 = load i32, i32* %p6, align 1, !tbaa !11 %p7 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 7 %7 = load i32, i32* %p7, align 1, !tbaa !12 %p8 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 8 %8 = load i32, i32* %p8, align 1, !tbaa !13 %p9 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 9 %9 = load i32, i32* %p9, align 1, !tbaa !14 %p10 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 10 %10 = load i32, i32* %p10, align 1, !tbaa !15 %p11 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 11 %11 = load i32, i32* %p11, align 1, !tbaa !16 %p12 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 12 %12 = load i32, i32* %p12, align 1, !tbaa !17 %p13 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 13 %13 = load i32, i32* %p13, align 1, !tbaa !18 %p14 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 14 %14 = load i32, i32* %p14, align 1, !tbaa !19 %p15 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 15 %15 = load i32, i32* %p15, align 1, !tbaa !20 %p16 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 16 %16 = load i32, i32* %p16, align 1, !tbaa !21 %p17 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 17 %17 = load i32, i32* %p17, align 1, !tbaa !22 %p18 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 18 %18 = load i32, i32* %p18, align 1, !tbaa !23 %p19 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 19 %19 = load i32, i32* %p19, align 1, !tbaa !24 %p20 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 20 %20 = load i32, i32* %p20, align 1, !tbaa !25 %p21 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 21 %21 = load i32, i32* %p21, align 1, !tbaa !26 %p22 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 22 %22 = load i32, i32* %p22, align 1, !tbaa !27 %p23 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 23 %23 = load i32, i32* %p23, align 1, !tbaa !28 %p24 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 24 %24 = load i32, i32* %p24, align 1, !tbaa !29 %p25 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 25 %25 = load i32, i32* %p25, align 1, !tbaa !30 %p26 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 26 %26 = load i32, i32* %p26, align 1, !tbaa !31 %p27 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 27 %27 = load i32, i32* %p27, align 1, !tbaa !32 %p28 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 28 %28 = load i32, i32* %p28, align 1, !tbaa !33 %p29 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 29 %29 = load i32, i32* %p29, align 1, !tbaa !34 %p30 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 30 %30 = load i32, i32* %p30, align 1, !tbaa !35 %p31 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 31 %31 = load i32, i32* %p31, align 1, !tbaa !36 %p32 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %s, i32 0, i32 32 %32 = load i32, i32* %p32, align 1, !tbaa !37 %add = add i8 %0, 1 store i8 %add, i8* %p0, align 1, !tbaa !1 %add2 = add i32 %1, 2 store i32 %add2, i32* %p1, align 1, !tbaa !6 %add3 = add i32 %2, 3 store i32 %add3, i32* %p2, align 1, !tbaa !7 %add4 = add i32 %3, 4 store i32 %add4, i32* %p3, align 1, !tbaa !8 %add5 = add i32 %4, 5 store i32 %add5, i32* %p4, align 1, !tbaa !9 %add6 = add i32 %5, 6 store i32 %add6, i32* %p5, align 1, !tbaa !10 %add7 = add i32 %6, 7 store i32 %add7, i32* %p6, align 1, !tbaa !11 %add8 = add i32 %7, 8 store i32 %add8, i32* %p7, align 1, !tbaa !12 %add9 = add i32 %8, 9 store i32 %add9, i32* %p8, align 1, !tbaa !13 %add10 = add i32 %9, 10 store i32 %add10, i32* %p9, align 1, !tbaa !14 %add11 = add i32 %10, 11 store i32 %add11, i32* %p10, align 1, !tbaa !15 %add12 = add i32 %11, 12 store i32 %add12, i32* %p11, align 1, !tbaa !16 %add13 = add i32 %12, 13 store i32 %add13, i32* %p12, align 1, !tbaa !17 %add14 = add i32 %13, 14 store i32 %add14, i32* %p13, align 1, !tbaa !18 %add15 = add i32 %14, 15 store i32 %add15, i32* %p14, align 1, !tbaa !19 %add16 = add i32 %15, 16 store i32 %add16, i32* %p15, align 1, !tbaa !20 %add17 = add i32 %16, 17 store i32 %add17, i32* %p16, align 1, !tbaa !21 %add18 = add i32 %17, 18 store i32 %add18, i32* %p17, align 1, !tbaa !22 %add19 = add i32 %18, 19 store i32 %add19, i32* %p18, align 1, !tbaa !23 %add20 = add i32 %19, 20 store i32 %add20, i32* %p19, align 1, !tbaa !24 %add21 = add i32 %20, 21 store i32 %add21, i32* %p20, align 1, !tbaa !25 %add22 = add i32 %21, 22 store i32 %add22, i32* %p21, align 1, !tbaa !26 %add23 = add i32 %22, 23 store i32 %add23, i32* %p22, align 1, !tbaa !27 %add24 = add i32 %23, 24 store i32 %add24, i32* %p23, align 1, !tbaa !28 %add25 = add i32 %24, 25 store i32 %add25, i32* %p24, align 1, !tbaa !29 %add26 = add i32 %25, 26 store i32 %add26, i32* %p25, align 1, !tbaa !30 %add27 = add i32 %26, 27 store i32 %add27, i32* %p26, align 1, !tbaa !31 %add28 = add i32 %27, 28 store i32 %add28, i32* %p27, align 1, !tbaa !32 %add29 = add i32 %28, 29 store i32 %add29, i32* %p28, align 1, !tbaa !33 %add30 = add i32 %29, 30 store i32 %add30, i32* %p29, align 1, !tbaa !34 %add31 = add i32 %30, 31 store i32 %add31, i32* %p30, align 1, !tbaa !35 %add32 = add i32 %31, 32 store i32 %add32, i32* %p31, align 1, !tbaa !36 %add33 = add i32 %32, 33 store i32 %add33, i32* %p32, align 1, !tbaa !37 %33 = getelementptr inbounds %struct.VeryLarge, %struct.VeryLarge* %agg.result, i32 0, i32 0 call void @llvm.memcpy.p0i8.p0i8.i32(i8* %33, i8* %p0, i32 129, i32 1, i1 false), !tbaa.struct !38 ret void } ; Function Attrs: argmemonly nounwind declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture readonly, i32, i32, i1) #1 attributes #0 = { norecurse nounwind "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #1 = { argmemonly nounwind } !llvm.ident = !{!0} !0 = !{!"clang version 3.8.0 (git://github.com/llvm-mirror/clang 40ef2b7531472c41212c4719a9294aeb7bddebbc) (git://github.com/llvm-mirror/llvm c601eaf55606dfb9ad372b514b77aa00d1409be1)"} !1 = !{!2, !3, i64 0} !2 = !{!"", !3, i64 0, !5, i64 1, !5, i64 5, !5, i64 9, !5, i64 13, !5, i64 17, !5, i64 21, !5, i64 25, !5, i64 29, !5, i64 33, !5, i64 37, !5, i64 41, !5, i64 45, !5, i64 49, !5, i64 53, !5, i64 57, !5, i64 61, !5, i64 65, !5, i64 69, !5, i64 73, !5, i64 77, !5, i64 81, !5, i64 85, !5, i64 89, !5, i64 93, !5, i64 97, !5, i64 101, !5, i64 105, !5, i64 109, !5, i64 113, !5, i64 117, !5, i64 121, !5, i64 125} !3 = !{!"omnipotent char", !4, i64 0} !4 = !{!"Simple C/C++ TBAA"} !5 = !{!"int", !3, i64 0} !6 = !{!2, !5, i64 1} !7 = !{!2, !5, i64 5} !8 = !{!2, !5, i64 9} !9 = !{!2, !5, i64 13} !10 = !{!2, !5, i64 17} !11 = !{!2, !5, i64 21} !12 = !{!2, !5, i64 25} !13 = !{!2, !5, i64 29} !14 = !{!2, !5, i64 33} !15 = !{!2, !5, i64 37} !16 = !{!2, !5, i64 41} !17 = !{!2, !5, i64 45} !18 = !{!2, !5, i64 49} !19 = !{!2, !5, i64 53} !20 = !{!2, !5, i64 57} !21 = !{!2, !5, i64 61} !22 = !{!2, !5, i64 65} !23 = !{!2, !5, i64 69} !24 = !{!2, !5, i64 73} !25 = !{!2, !5, i64 77} !26 = !{!2, !5, i64 81} !27 = !{!2, !5, i64 85} !28 = !{!2, !5, i64 89} !29 = !{!2, !5, i64 93} !30 = !{!2, !5, i64 97} !31 = !{!2, !5, i64 101} !32 = !{!2, !5, i64 105} !33 = !{!2, !5, i64 109} !34 = !{!2, !5, i64 113} !35 = !{!2, !5, i64 117} !36 = !{!2, !5, i64 121} !37 = !{!2, !5, i64 125} !38 = !{i64 0, i64 1, !39, i64 1, i64 4, !40, i64 5, i64 4, !40, i64 9, i64 4, !40, i64 13, i64 4, !40, i64 17, i64 4, !40, i64 21, i64 4, !40, i64 25, i64 4, !40, i64 29, i64 4, !40, i64 33, i64 4, !40, i64 37, i64 4, !40, i64 41, i64 4, !40, i64 45, i64 4, !40, i64 49, i64 4, !40, i64 53, i64 4, !40, i64 57, i64 4, !40, i64 61, i64 4, !40, i64 65, i64 4, !40, i64 69, i64 4, !40, i64 73, i64 4, !40, i64 77, i64 4, !40, i64 81, i64 4, !40, i64 85, i64 4, !40, i64 89, i64 4, !40, i64 93, i64 4, !40, i64 97, i64 4, !40, i64 101, i64 4, !40, i64 105, i64 4, !40, i64 109, i64 4, !40, i64 113, i64 4, !40, i64 117, i64 4, !40, i64 121, i64 4, !40, i64 125, i64 4, !40} !39 = !{!3, !3, i64 0} !40 = !{!5, !5, i64 0} ``` Reviewers: asl Subscribers: qcolombet Differential Revision: http://reviews.llvm.org/D17441 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261746 91177308-0d34-0410-b5e6-96231b3b80d8

Summary: This reverts commit d88cc08. #0 0xfed467 in llvm::ARMFrameLowering::determineCalleeSaves(llvm::MachineFunction&, llvm::BitVector&, llvm::RegScavenger*) const /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/Target/ARM/ARMFrameLowering.cpp:1625:52 #1 0x330d4cc in (anonymous namespace)::PEI::runOnMachineFunction(llvm::MachineFunction&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/CodeGen/PrologEpilogInserter.cpp:186:3 #2 0x3193e12 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/CodeGen/MachineFunctionPass.cpp:60:13 #3 0x396237d in llvm::FPPassManager::runOnFunction(llvm::Function&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/LegacyPassManager.cpp:1526:23 #4 0x3962a23 in llvm::FPPassManager::runOnModule(llvm::Module&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/LegacyPassManager.cpp:1547:16 #5 0x3963d52 in runOnModule /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/LegacyPassManager.cpp:1603:23 #6 0x3963d52 in llvm::legacy::PassManagerImpl::run(llvm::Module&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/LegacyPassManager.cpp:1706 #7 0x6bb910 in compileModule(char**, llvm::LLVMContext&) /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/tools/llc/llc.cpp:412:5 #8 0x6b3c25 in main /mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm/tools/llc/llc.cpp:218:22 #9 0x7fd4a7d37ec4 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21ec4) #10 0x625c93 in _start (/mnt/b/sanitizer-buildbot2/sanitizer-x86_64-linux-bootstrap/build/llvm_build_msan/bin/llc+0x625c93) Reviewers: Subscribers: git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268536 91177308-0d34-0410-b5e6-96231b3b80d8

Reverse iterators to doubly-linked lists can be simpler (and cheaper) than std::reverse_iterator. Make it so. In particular, change ilist<T>::reverse_iterator so that it is *never* invalidated unless the node it references is deleted. This matches the guarantees of ilist<T>::iterator. (Note: MachineBasicBlock::iterator is *not* an ilist iterator, but a MachineInstrBundleIterator<MachineInstr>. This commit does not change MachineBasicBlock::reverse_iterator, but it does update MachineBasicBlock::reverse_instr_iterator. See note at end of commit message for details on bundle iterators.) Given the list (with the Sentinel showing twice for simplicity): [Sentinel] <-> A <-> B <-> [Sentinel] the following is now true: 1. begin() represents A. 2. begin() holds the pointer for A. 3. end() represents [Sentinel]. 4. end() holds the poitner for [Sentinel]. 5. rbegin() represents B. 6. rbegin() holds the pointer for B. 7. rend() represents [Sentinel]. 8. rend() holds the pointer for [Sentinel]. The changes are #6 and #8. Here are some properties from the old scheme (which used std::reverse_iterator): - rbegin() held the pointer for [Sentinel] and rend() held the pointer for A; - operator*() cost two dereferences instead of one; - converting from a valid iterator to its valid reverse_iterator involved a confusing increment; and - "RI++->erase()" left RI invalid. The unintuitive replacement was "RI->erase(), RE = end()". With vector-like data structures these properties are hard to avoid (since past-the-beginning is not a valid pointer), and don't impose a real cost (since there's still only one dereference, and all iterators are invalidated on erase). But with lists, this was a poor design. Specifically, the following code (which obviously works with normal iterators) now works with ilist::reverse_iterator as well: for (auto RI = L.rbegin(), RE = L.rend(); RI != RE;) fooThatMightRemoveArgFromList(*RI++); Converting between iterator and reverse_iterator for the same node uses the getReverse() function. reverse_iterator iterator::getReverse(); iterator reverse_iterator::getReverse(); Why doesn't iterator <=> reverse_iterator conversion use constructors? In order to catch and update old code, reverse_iterator does not even have an explicit conversion from iterator. It wouldn't be safe because there would be no reasonable way to catch all the bugs from the changed semantic (see the changes at call sites that are part of this patch). Old code used this API: std::reverse_iterator::reverse_iterator(iterator); iterator std::reverse_iterator::base(); Here's how to update from old code to new (that incorporates the semantic change), assuming I is an ilist<>::iterator and RI is an ilist<>::reverse_iterator: [Old] ==> [New] reverse_iterator(I) (--I).getReverse() reverse_iterator(I) ++I.getReverse() --reverse_iterator(I) I.getReverse() reverse_iterator(++I) I.getReverse() RI.base() (--RI).getReverse() RI.base() ++RI.getReverse() --RI.base() RI.getReverse() (++RI).base() RI.getReverse() delete &*RI, RE = end() delete &*RI++ RI->erase(), RE = end() RI++->erase() ======================================= Note: bundle iterators are out of scope ======================================= MachineBasicBlock::iterator, also known as MachineInstrBundleIterator<MachineInstr>, is a wrapper to represent MachineInstr bundles. The idea is that each operator++ takes you to the beginning of the next bundle. Implementing a sane reverse iterator for this is harder than ilist. Here are the options: - Use std::reverse_iterator<MBB::i>. Store a handle to the beginning of the next bundle. A call to operator*() runs a loop (usually operator--() will be called 1 time, for unbundled instructions). Increment/decrement just works. This is the status quo. - Store a handle to the final node in the bundle. A call to operator*() still runs a loop, but it iterates one time fewer (usually operator--() will be called 0 times, for unbundled instructions). Increment/decrement just works. - Make the ilist_sentinel<MachineInstr> *always* store that it's the sentinel (instead of just in asserts mode). Then the bundle iterator can sniff the sentinel bit in operator++(). I initially tried implementing the end() option as part of this commit, but updating iterator/reverse_iterator conversion call sites was error-prone. I have a WIP series of patches that implements the final option. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280032 91177308-0d34-0410-b5e6-96231b3b80d8

dylanmckay added the enhancement label Nov 29, 2014

dylanmckay closed this as completed Jan 23, 2015

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Support 'section' attribute #8

Support 'section' attribute #8

4ntoine commented Nov 26, 2014

dylanmckay commented Dec 30, 2014

Support 'section' attribute #8

Support 'section' attribute #8

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4ntoine commented Nov 26, 2014

dylanmckay commented Dec 30, 2014