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release/18.x: [PPCMergeStringPool] Only replace constant once (#92996) #93442

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Merged
merged 1 commit into from
Jun 4, 2024
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release/18.x: [PPCMergeStringPool] Only replace constant once (#92996) #93442

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37 changes: 7 additions & 30 deletions llvm/lib/Target/PowerPC/PPCMergeStringPool.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -290,13 +290,6 @@ bool PPCMergeStringPool::mergeModuleStringPool(Module &M) {
return true;
}

static bool userHasOperand(User *TheUser, GlobalVariable *GVOperand) {
for (Value *Op : TheUser->operands())
if (Op == GVOperand)
return true;
return false;
}

// For pooled strings we need to add the offset into the pool for each string.
// This is done by adding a Get Element Pointer (GEP) before each user. This
// function adds the GEP.
Expand All @@ -307,29 +300,13 @@ void PPCMergeStringPool::replaceUsesWithGEP(GlobalVariable *GlobalToReplace,
Indices.push_back(ConstantInt::get(Type::getInt32Ty(*Context), 0));
Indices.push_back(ConstantInt::get(Type::getInt32Ty(*Context), ElementIndex));

// Need to save a temporary copy of each user list because we remove uses
// as we replace them.
SmallVector<User *> Users;
for (User *CurrentUser : GlobalToReplace->users())
Users.push_back(CurrentUser);

for (User *CurrentUser : Users) {
// The user was not found so it must have been replaced earlier.
if (!userHasOperand(CurrentUser, GlobalToReplace))
continue;

// We cannot replace operands in globals so we ignore those.
if (isa<GlobalValue>(CurrentUser))
continue;

Constant *ConstGEP = ConstantExpr::getInBoundsGetElementPtr(
PooledStructType, GPool, Indices);
LLVM_DEBUG(dbgs() << "Replacing this global:\n");
LLVM_DEBUG(GlobalToReplace->dump());
LLVM_DEBUG(dbgs() << "with this:\n");
LLVM_DEBUG(ConstGEP->dump());
GlobalToReplace->replaceAllUsesWith(ConstGEP);
}
Constant *ConstGEP =
ConstantExpr::getInBoundsGetElementPtr(PooledStructType, GPool, Indices);
LLVM_DEBUG(dbgs() << "Replacing this global:\n");
LLVM_DEBUG(GlobalToReplace->dump());
LLVM_DEBUG(dbgs() << "with this:\n");
LLVM_DEBUG(ConstGEP->dump());
GlobalToReplace->replaceAllUsesWith(ConstGEP);
}

} // namespace
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20 changes: 20 additions & 0 deletions llvm/test/CodeGen/PowerPC/mergeable-string-pool-pr92991.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu < %s | FileCheck %s

@g = private constant [4 x i32] [i32 122, i32 67, i32 35, i32 56]
@g2 = private constant [1 x i64] [i64 1], align 8

define void @test(ptr %p, ptr %p2) {
; CHECK-LABEL: test:
; CHECK: # %bb.0:
; CHECK-NEXT: addis 5, 2, .L__ModuleStringPool@toc@ha
; CHECK-NEXT: addi 5, 5, .L__ModuleStringPool@toc@l
; CHECK-NEXT: addi 6, 5, 12
; CHECK-NEXT: std 6, 0(3)
; CHECK-NEXT: addi 3, 5, 16
; CHECK-NEXT: std 3, 0(4)
; CHECK-NEXT: blr
store ptr getelementptr inbounds ([4 x i32], ptr @g, i64 0, i64 1), ptr %p
store ptr getelementptr inbounds ([4 x i32], ptr @g, i64 0, i64 2), ptr %p2
ret void
}
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