[SDAG] Miscompile at O3

[dtcxzyw]

Reproducer:

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

@b = dso_local local_unnamed_addr global i64 4073709551615, align 8
@c = dso_local global i8 0, align 1
@e = dso_local local_unnamed_addr global ptr @c, align 8
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1

define i32 @main() {
entry:
  %0 = load ptr, ptr @e, align 8
  %1 = load i8, ptr %0, align 1
  %tobool.not.i = icmp eq i8 %1, 0
  %2 = load i64, ptr @b, align 8
  %and.i = shl i64 %2, 48
  %sub.i.i = and i64 %and.i, 5098637728136822784
  %sext.i = add i64 %sub.i.i, 1688849860263936
  %conv3.i = lshr i64 %sext.i, 48
  %and4.i = and i64 %conv3.i, %2
  %conv = trunc i64 %and4.i to i32
  %call1 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str, i32 noundef %conv)
  ret i32 0
}

declare noundef i32 @printf(ptr noundef readonly captures(none), ...)

> ./bin/lli test.ll
2080507592
> ./bin/lli -fast-isel test.ll
1736
> ./llubi --max-steps 1000000 test.ll
1736

[dtcxzyw]

Reduced:

define i64 @test(i64 %x) {
entry:
  %shl = shl i64 %x, 48
  %and = and i64 %shl, 5098637728136822784
  %add = add i64 %and, 1688849860263936
  %lshr = lshr i64 %add, 48
  %res = and i64 %lshr, %x
  ret i64 %res
}

test:
        movl    %edi, %eax
        andl    $18114, %eax                    # imm = 0x46C2
        addl    $-65530, %eax                   # imm = 0xFFFF0006
        andl    %edi, %eax
        retq

[llvmbot]

@llvm/issue-subscribers-backend-x86

Author: Yingwei Zheng (dtcxzyw)

Reproducer: ``` target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu"

@b = dso_local local_unnamed_addr global i64 4073709551615, align 8
@c = dso_local global i8 0, align 1
@e = dso_local local_unnamed_addr global ptr @c, align 8
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1

define i32 @main() {
entry:
%0 = load ptr, ptr @e, align 8
%1 = load i8, ptr %0, align 1
%tobool.not.i = icmp eq i8 %1, 0
%2 = load i64, ptr @b, align 8
%and.i = shl i64 %2, 48
%sub.i.i = and i64 %and.i, 5098637728136822784
%sext.i = add i64 %sub.i.i, 1688849860263936
%conv3.i = lshr i64 %sext.i, 48
%and4.i = and i64 %conv3.i, %2
%conv = trunc i64 %and4.i to i32
%call1 = tail call i32 (ptr, ...) @printf(ptr noundef nonnull dereferenceable(1) @.str, i32 noundef %conv)
ret i32 0
}

declare noundef i32 @printf(ptr noundef readonly captures(none), ...)

> ./bin/lli test.ll
2080507592
> ./bin/lli -fast-isel test.ll
1736
> ./llubi --max-steps 1000000 test.ll
1736

</details>

[dtcxzyw]

Caused by #126448.