Use getSignedTargetConstant for offset

[scui-ibm]

This is to fix an assertion failure with PeepholePPC64. The load/store offset can be negative. A reduced case from one of our failures is added as well.

[llvmbot]

@llvm/pr-subscribers-backend-powerpc

Author: Shimin Cui (scui-ibm)

Changes

This is to fix an assertion failure with PeepholePPC64. The load/store offset can be negative. A reduced case from one of our failures is added as well.

---

Full diff: https://github.com/llvm/llvm-project/pull/141149.diff

2 Files Affected:

• (modified) llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp (+2-2)
• (added) llvm/test/CodeGen/PowerPC/signed-offset.ll (+33)

diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp index 7147506bbd89b..f921032356d65 100644 --- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp +++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp @@ -7858,8 +7858,8 @@ void PPCDAGToDAGISel::PeepholePPC64() { if (!isInt<16>(Offset)) continue; - ImmOpnd = CurDAG->getTargetConstant(Offset, SDLoc(ImmOpnd), - ImmOpnd.getValueType()); + ImmOpnd = CurDAG->getSignedTargetConstant(Offset, SDLoc(ImmOpnd), + ImmOpnd.getValueType()); } else if (Offset != 0) { // This optimization is performed for non-TOC-based local-[exec|dynamic] // accesses. diff --git a/llvm/test/CodeGen/PowerPC/signed-offset.ll b/llvm/test/CodeGen/PowerPC/signed-offset.ll new file mode 100644 index 0000000000000..d12f99ead644b --- /dev/null +++ b/llvm/test/CodeGen/PowerPC/signed-offset.ll @@ -0,0 +1,33 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5 +; RUN: llc -verify-machineinstrs < %s -mcpu=ppc -mtriple powerpc-ibm-aix-xcoff | FileCheck %s + +%_type = type <{ [90112 x i8] }> + +@g = external global %_type + +define void @foo(ptr %p) { +; CHECK-LABEL: foo: +; CHECK: stfd 31, 0(31) +; CHECK-NEXT: lwz 3, -32(30) +; CHECK-NEXT: lwz 4, -28(30) +; CHECK-NEXT: cmplwi 3, 0 +; CHECK-NEXT: cmpwi 1, 3, 0 +; CHECK-NEXT: crandc 20, 5, 2 +; CHECK-NEXT: cmpwi 1, 4, 0 +entry: + %0 = load double, ptr getelementptr inbounds nuw (i8, ptr @g, i32 83272), align 8 + %1 = call i32 @bar(ptr getelementptr inbounds nuw (i8, ptr @g, i32 83272)) + %2 = call i32 @bar(ptr getelementptr inbounds nuw (i8, ptr @g, i32 83240)) + store double %0, ptr %p, align 8 + %3 = load i64, ptr getelementptr inbounds nuw (i8, ptr @g, i32 83240), align 8 + %4 = icmp slt i64 %3, 1 + br i1 %4, label %then, label %else + +then: ; preds = %entry + ret void + +else: ; preds = %entry + ret void +} + +declare signext i32 @bar(ptr) 

[topperc]

LGTM

[amy-kwan]

I think this LGTM.