From c8aed98a224b71a9ac5d6f3208ba733f12df8d53 Mon Sep 17 00:00:00 2001 From: Vladimir Radosavljevic <129192835+vladimirradosavljevic@users.noreply.github.com> Date: Fri, 10 Oct 2025 12:52:52 +0200 Subject: [PATCH] [CGP] Fix missing sign extension for base offset in optimizeMemoryInst (#161377) If we have integers larger than 64-bit we need to explicitly sign extend them, otherwise we will get wrong zero extended values. --- llvm/lib/CodeGen/CodeGenPrepare.cpp | 6 +- .../CodeGenPrepare/X86/baseoffs-sext-bug.ll | 81 +++++++++++++++++++ 2 files changed, 84 insertions(+), 3 deletions(-) create mode 100644 llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp index 355c7ef1d619..b9af8a62459d 100644 --- a/llvm/lib/CodeGen/CodeGenPrepare.cpp +++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp @@ -2845,7 +2845,7 @@ struct ExtAddrMode : public TargetLowering::AddrMode { case ScaledRegField: return ScaledReg; case BaseOffsField: - return ConstantInt::get(IntPtrTy, BaseOffs); + return ConstantInt::getSigned(IntPtrTy, BaseOffs); } } @@ -5706,7 +5706,7 @@ bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr, // Add in the Base Offset if present. if (AddrMode.BaseOffs) { - Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs); + Value *V = ConstantInt::getSigned(IntPtrTy, AddrMode.BaseOffs); if (ResultIndex) { // We need to add this separately from the scale above to help with // SDAG consecutive load/store merging. @@ -5825,7 +5825,7 @@ bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr, // Add in the Base Offset if present. if (AddrMode.BaseOffs) { - Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs); + Value *V = ConstantInt::getSigned(IntPtrTy, AddrMode.BaseOffs); if (Result) Result = Builder.CreateAdd(Result, V, "sunkaddr"); else diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll new file mode 100644 index 000000000000..51a461e61d88 --- /dev/null +++ b/llvm/test/Transforms/CodeGenPrepare/X86/baseoffs-sext-bug.ll @@ -0,0 +1,81 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6 +; RUN: opt -S -passes='require,function(codegenprepare)' < %s | FileCheck --check-prefix=GEP %s +; RUN: opt -S -passes='require,function(codegenprepare)' -addr-sink-using-gep=false < %s | FileCheck --check-prefix=NO-GEP %s + +target triple = "x86_64--linux-gnu" +target datalayout = "e-m:e-p0:128:128-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" +; -p0:128:128 is added to ensure that transformation will be triggered. + +define i128 @test(i128 %arg) { +; GEP-LABEL: define i128 @test( +; GEP-SAME: i128 [[ARG:%.*]]) { +; GEP-NEXT: [[ENTRY:.*]]: +; GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10 +; GEP-NEXT: br i1 [[CMP]], label %[[THEN:.*]], label %[[EXIT:.*]] +; GEP: [[THEN]]: +; GEP-NEXT: [[SUNKADDR:%.*]] = inttoptr i128 [[ARG]] to ptr +; GEP-NEXT: [[SUNKADDR1:%.*]] = getelementptr i8, ptr [[SUNKADDR]], i128 -32 +; GEP-NEXT: [[LOAD:%.*]] = load i128, ptr [[SUNKADDR1]], align 16 +; GEP-NEXT: br label %[[EXIT]] +; GEP: [[EXIT]]: +; GEP-NEXT: [[PHI:%.*]] = phi i128 [ [[LOAD]], %[[THEN]] ], [ 0, %[[ENTRY]] ] +; GEP-NEXT: ret i128 [[PHI]] +; +; NO-GEP-LABEL: define i128 @test( +; NO-GEP-SAME: i128 [[ARG:%.*]]) { +; NO-GEP-NEXT: [[ENTRY:.*]]: +; NO-GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10 +; NO-GEP-NEXT: br i1 [[CMP]], label %[[THEN:.*]], label %[[EXIT:.*]] +; NO-GEP: [[THEN]]: +; NO-GEP-NEXT: [[SUNKADDR:%.*]] = add i128 [[ARG]], -32 +; NO-GEP-NEXT: [[SUNKADDR1:%.*]] = inttoptr i128 [[SUNKADDR]] to ptr +; NO-GEP-NEXT: [[LOAD:%.*]] = load i128, ptr [[SUNKADDR1]], align 16 +; NO-GEP-NEXT: br label %[[EXIT]] +; NO-GEP: [[EXIT]]: +; NO-GEP-NEXT: [[PHI:%.*]] = phi i128 [ [[LOAD]], %[[THEN]] ], [ 0, %[[ENTRY]] ] +; NO-GEP-NEXT: ret i128 [[PHI]] +; +entry: + %add = add i128 %arg, -32 + %cmp = icmp ugt i128 %arg, 10 + br i1 %cmp, label %then, label %exit + +then: + %inttoptr = inttoptr i128 %add to ptr + %load = load i128, ptr %inttoptr, align 16 + br label %exit + +exit: + %phi = phi i128 [ %load, %then ], [ 0, %entry ] + ret i128 %phi +} + +define void @test_combine(ptr %ptr, i128 %arg) { +; GEP-LABEL: define void @test_combine( +; GEP-SAME: ptr [[PTR:%.*]], i128 [[ARG:%.*]]) { +; GEP-NEXT: [[ENTRY:.*:]] +; GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10 +; GEP-NEXT: [[SELECT1:%.*]] = select i1 [[CMP]], i128 -32, i128 0 +; GEP-NEXT: [[SUNKADDR:%.*]] = getelementptr inbounds i8, ptr [[PTR]], i128 [[SELECT1]] +; GEP-NEXT: store i128 1, ptr [[SUNKADDR]], align 16 +; GEP-NEXT: ret void +; +; NO-GEP-LABEL: define void @test_combine( +; NO-GEP-SAME: ptr [[PTR:%.*]], i128 [[ARG:%.*]]) { +; NO-GEP-NEXT: [[ENTRY:.*:]] +; NO-GEP-NEXT: [[CMP:%.*]] = icmp ugt i128 [[ARG]], 10 +; NO-GEP-NEXT: [[SELECT1:%.*]] = select i1 [[CMP]], i128 -32, i128 0 +; NO-GEP-NEXT: [[SUNKADDR:%.*]] = ptrtoint ptr [[PTR]] to i128 +; NO-GEP-NEXT: [[SUNKADDR2:%.*]] = add i128 [[SUNKADDR]], [[SELECT1]] +; NO-GEP-NEXT: [[SUNKADDR3:%.*]] = inttoptr i128 [[SUNKADDR2]] to ptr +; NO-GEP-NEXT: store i128 1, ptr [[SUNKADDR3]], align 16 +; NO-GEP-NEXT: ret void +; +entry: + %cmp = icmp ugt i128 %arg, 10 + %gep = getelementptr inbounds i8, ptr %ptr, i128 -32 + %select = select i1 %cmp, ptr %gep, ptr %ptr + store i128 1, ptr %select, align 16 + ret void +} +