diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp --- a/llvm/lib/Target/X86/X86InstrInfo.cpp +++ b/llvm/lib/Target/X86/X86InstrInfo.cpp @@ -4462,6 +4462,11 @@ return false; case X86::COND_G: case X86::COND_GE: case X86::COND_L: case X86::COND_LE: + // If SF is used, but the instruction doesn't update the SF, then we + // can't do the optimization. + if (NoSignFlag) + return false; + LLVM_FALLTHROUGH; case X86::COND_O: case X86::COND_NO: // If OF is used, the instruction needs to clear it like CmpZero does. if (!ClearsOverflowFlag) diff --git a/llvm/test/CodeGen/X86/pr56103.ll b/llvm/test/CodeGen/X86/pr56103.ll new file mode 100644 --- /dev/null +++ b/llvm/test/CodeGen/X86/pr56103.ll @@ -0,0 +1,65 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py +; RUN: llc < %s -mtriple=x86_64-linux-generic | FileCheck %s + +@e = global i16 0, align 2 +@a = global i32 0, align 4 +@c = global i32 0, align 4 +@b = global i64 0, align 8 + +; Check the test instruction won't be optimizated by peephole opt. + +define dso_local i32 @main() nounwind { +; CHECK-LABEL: main: +; CHECK: # %bb.0: # %entry +; CHECK-NEXT: pushq %rax +; CHECK-NEXT: movq e@GOTPCREL(%rip), %rax +; CHECK-NEXT: movw $1, (%rax) +; CHECK-NEXT: movq b@GOTPCREL(%rip), %rax +; CHECK-NEXT: movq $1, (%rax) +; CHECK-NEXT: movq a@GOTPCREL(%rip), %rax +; CHECK-NEXT: movl (%rax), %ecx +; CHECK-NEXT: movl $-2, %eax +; CHECK-NEXT: sarl %cl, %eax +; CHECK-NEXT: movq c@GOTPCREL(%rip), %rdx +; CHECK-NEXT: movl (%rdx), %edx +; CHECK-NEXT: decl %edx +; CHECK-NEXT: movzwl %ax, %eax +; CHECK-NEXT: decl %eax +; CHECK-NEXT: xorl %edx, %eax +; CHECK-NEXT: notl %ecx +; CHECK-NEXT: andl %eax, %ecx +; CHECK-NEXT: testq %rcx, %rcx +; CHECK-NEXT: jle .LBB0_2 +; CHECK-NEXT: # %bb.1: # %if.end +; CHECK-NEXT: xorl %eax, %eax +; CHECK-NEXT: popq %rcx +; CHECK-NEXT: retq +; CHECK-NEXT: .LBB0_2: # %if.then +; CHECK-NEXT: callq abort@PLT +entry: + store i16 1, ptr @e, align 2 + store i64 1, ptr @b, align 8 + %0 = load i32, ptr @a, align 4 + %shr = ashr i32 -2, %0 + %1 = load i32, ptr @c, align 4 + %sub = add i32 %1, -1 + %conv2 = zext i32 %sub to i64 + %2 = and i32 %shr, 65535 + %conv3 = zext i32 %2 to i64 + %sub4 = add nsw i64 %conv3, -1 + %xor = xor i64 %sub4, %conv2 + %neg5 = xor i32 %0, -1 + %conv6 = sext i32 %neg5 to i64 + %and = and i64 %xor, %conv6 + %cmp = icmp slt i64 %and, 1 + br i1 %cmp, label %if.then, label %if.end + +if.then: ; preds = %entry + call void @abort() #2 + unreachable + +if.end: ; preds = %entry + ret i32 0 +} + +declare void @abort()