Rebase

Author: dtcxzyw

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -7161,7 +7161,7 @@ static bool switchToLookupTable(SwitchInst *SI, IRBuilder<> &Builder,
 
 /// Try to reduce the range of cases with an unreachable default.
 static bool
-ReduceSwitchRangeWithUnreachableDefault(SwitchInst *SI,
+reduceSwitchRangeWithUnreachableDefault(SwitchInst *SI,
                                         const SmallVectorImpl<int64_t> &Values,
                                         uint64_t Base, IRBuilder<> &Builder) {
   bool HasDefault =
@@ -7203,12 +7203,14 @@ ReduceSwitchRangeWithUnreachableDefault(SwitchInst *SI,
         CommonBits);
 
   llvm::sort(NewValues);
-  if (!isSwitchDense(NewValues))
+  if (!isSwitchDense(NewValues)) {
     // Transform didn't create a dense switch.
     return false;
+  }
 
   auto *Ty = cast<IntegerType>(SI->getCondition()->getType());
-  APInt Offset(Ty->getBitWidth(), BestOffset - Base);
+  APInt Offset(Ty->getBitWidth(), BestOffset - Base, /*isSigned=*/true,
+               /*implicitTrunc=*/true);
   auto *Index = Builder.CreateAnd(
       Builder.CreateAdd(SI->getCondition(), ConstantInt::get(Ty, Offset)),
       Mask);
@@ -7261,7 +7263,7 @@ static bool reduceSwitchRange(SwitchInst *SI, IRBuilder<> &Builder,
   for (auto &V : Values)
     V -= (uint64_t)(Base);
 
-  if (ReduceSwitchRangeWithUnreachableDefault(SI, Values, Base, Builder))
+  if (reduceSwitchRangeWithUnreachableDefault(SI, Values, Base, Builder))
     return true;
 
   // Now we have signed numbers that have been shifted so that, given enough

llvm/test/Transforms/SimplifyCFG/RISCV/switch-of-powers-of-two.ll

@@ -157,22 +157,10 @@ return:
 define i32 @unable_to_create_dense_switch(i32 %x) {
 ; CHECK-LABEL: @unable_to_create_dense_switch(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    switch i32 [[X:%.*]], label [[DEFAULT_CASE:%.*]] [
-; CHECK-NEXT:      i32 1, label [[RETURN:%.*]]
-; CHECK-NEXT:      i32 2, label [[BB3:%.*]]
-; CHECK-NEXT:      i32 4, label [[BB4:%.*]]
-; CHECK-NEXT:      i32 4096, label [[BB5:%.*]]
-; CHECK-NEXT:    ]
-; CHECK:       default_case:
-; CHECK-NEXT:    unreachable
-; CHECK:       bb3:
-; CHECK-NEXT:    br label [[RETURN]]
-; CHECK:       bb4:
-; CHECK-NEXT:    br label [[RETURN]]
-; CHECK:       bb5:
-; CHECK-NEXT:    br label [[RETURN]]
-; CHECK:       return:
-; CHECK-NEXT:    [[P:%.*]] = phi i32 [ 1, [[BB3]] ], [ 0, [[BB4]] ], [ 42, [[BB5]] ], [ 2, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i32 [[X:%.*]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[TMP0]], 4095
+; CHECK-NEXT:    [[SWITCH_GEP:%.*]] = getelementptr inbounds [5 x i32], ptr @switch.table.unable_to_create_dense_switch, i32 0, i32 [[TMP1]]
+; CHECK-NEXT:    [[P:%.*]] = load i32, ptr [[SWITCH_GEP]], align 4
 ; CHECK-NEXT:    ret i32 [[P]]
 ;
 entry:
@@ -200,11 +188,13 @@ declare i32 @bar(i32)
 define i32 @unable_to_generate_lookup_table(i32 %x, i32 %y) {
 ; RV64I-LABEL: @unable_to_generate_lookup_table(
 ; RV64I-NEXT:  entry:
-; RV64I-NEXT:    switch i32 [[Y:%.*]], label [[DEFAULT_CASE:%.*]] [
+; RV64I-NEXT:    [[TMP0:%.*]] = add i32 [[Y1:%.*]], 0
+; RV64I-NEXT:    [[Y:%.*]] = and i32 [[TMP0]], 63
+; RV64I-NEXT:    switch i32 [[Y]], label [[DEFAULT_CASE:%.*]] [
 ; RV64I-NEXT:      i32 1, label [[BB2:%.*]]
 ; RV64I-NEXT:      i32 2, label [[BB3:%.*]]
 ; RV64I-NEXT:      i32 8, label [[BB4:%.*]]
-; RV64I-NEXT:      i32 64, label [[BB5:%.*]]
+; RV64I-NEXT:      i32 0, label [[BB5:%.*]]
 ; RV64I-NEXT:    ]
 ; RV64I:       default_case:
 ; RV64I-NEXT:    unreachable

llvm/test/Transforms/SimplifyCFG/rangereduce.ll

@@ -369,9 +369,9 @@ define i8 @reduce_masked_common_high_bits_fail(i32 %0) {
 ; CHECK-LABEL: @reduce_masked_common_high_bits_fail(
 ; CHECK-NEXT:  start:
 ; CHECK-NEXT:    switch i32 [[TMP0:%.*]], label [[BB2:%.*]] [
-; CHECK-NEXT:    i32 128, label [[BB5:%.*]]
-; CHECK-NEXT:    i32 129, label [[BB4:%.*]]
-; CHECK-NEXT:    i32 511, label [[BB1:%.*]]
+; CHECK-NEXT:      i32 128, label [[BB5:%.*]]
+; CHECK-NEXT:      i32 129, label [[BB4:%.*]]
+; CHECK-NEXT:      i32 511, label [[BB1:%.*]]
 ; CHECK-NEXT:    ]
 ; CHECK:       bb2:
 ; CHECK-NEXT:    unreachable
@@ -409,19 +409,18 @@ define i8 @reduce_masked_default_reachable(i32 %0) {
 ; CHECK-LABEL: @reduce_masked_default_reachable(
 ; CHECK-NEXT:  start:
 ; CHECK-NEXT:    switch i32 [[TMP0:%.*]], label [[COMMON_RET:%.*]] [
-; CHECK-NEXT:    i32 0, label [[BB5:%.*]]
-; CHECK-NEXT:    i32 1, label [[BB4:%.*]]
-; CHECK-NEXT:    i32 255, label [[BB1:%.*]]
+; CHECK-NEXT:      i32 0, label [[BB5:%.*]]
+; CHECK-NEXT:      i32 1, label [[BB4:%.*]]
+; CHECK-NEXT:      i32 255, label [[BB1:%.*]]
 ; CHECK-NEXT:    ]
 ; CHECK:       common.ret:
-; CHECK-NEXT:    [[COMMON_RET_OP:%.*]] = phi i8 [ [[DOT0:%.*]], [[BB5]] ], [ 24, [[START:%.*]] ]
+; CHECK-NEXT:    [[COMMON_RET_OP:%.*]] = phi i8 [ 24, [[START:%.*]] ], [ -1, [[BB1]] ], [ 1, [[BB4]] ], [ 0, [[BB5]] ]
 ; CHECK-NEXT:    ret i8 [[COMMON_RET_OP]]
 ; CHECK:       bb4:
-; CHECK-NEXT:    br label [[BB5]]
+; CHECK-NEXT:    br label [[COMMON_RET]]
 ; CHECK:       bb1:
-; CHECK-NEXT:    br label [[BB5]]
+; CHECK-NEXT:    br label [[COMMON_RET]]
 ; CHECK:       bb5:
-; CHECK-NEXT:    [[DOT0]] = phi i8 [ -1, [[BB1]] ], [ 1, [[BB4]] ], [ 0, [[START]] ]
 ; CHECK-NEXT:    br label [[COMMON_RET]]
 ;
 start: