[llvm] [InstCombine]PtrReplacer: Correctly handle select with unavailable operands (PR #148829)
Pierre van Houtryve via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 16 00:28:36 PDT 2025
https://github.com/Pierre-vh updated https://github.com/llvm/llvm-project/pull/148829
>From d01533ac8cb6acc06b3321ca772fba407983f420 Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Tue, 15 Jul 2025 13:27:16 +0200
Subject: [PATCH 1/3] [InstCombine]PtrReplacer: Correctly handle select with
unavailable operands
The testcase I added previously failed because a SelectInst with invalid operands was created (one side `addrspace(4)`, the other `addrspace(5)`).
PointerReplacer needs to dig deeper if the true and/or false instructions of the select are not available.
Fixes SWDEV-542957
---
.../InstCombineLoadStoreAlloca.cpp | 28 ++++++++++++++-----
...ptr-replacer-select-addrspacecast-crash.ll | 20 +++++++++++++
2 files changed, 41 insertions(+), 7 deletions(-)
create mode 100644 llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index e791bc4b56e52..2cc1bc9fa4a67 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -277,6 +277,15 @@ bool PointerReplacer::collectUsers() {
Worklist.emplace_back(I);
};
+ auto TryPushInstOperand = [&](Instruction *InstOp) {
+ if (!UsersToReplace.contains(InstOp)) {
+ if (!ValuesToRevisit.insert(InstOp))
+ return false;
+ Worklist.emplace_back(InstOp);
+ }
+ return true;
+ };
+
PushUsersToWorklist(&Root);
while (!Worklist.empty()) {
Instruction *Inst = Worklist.pop_back_val();
@@ -309,12 +318,8 @@ bool PointerReplacer::collectUsers() {
// incoming values.
Worklist.emplace_back(PHI);
for (unsigned Idx = 0; Idx < PHI->getNumIncomingValues(); ++Idx) {
- auto *IncomingValue = cast<Instruction>(PHI->getIncomingValue(Idx));
- if (UsersToReplace.contains(IncomingValue))
- continue;
- if (!ValuesToRevisit.insert(IncomingValue))
+ if (!TryPushInstOperand(cast<Instruction>(PHI->getIncomingValue(Idx))))
return false;
- Worklist.emplace_back(IncomingValue);
}
} else if (auto *SI = dyn_cast<SelectInst>(Inst)) {
auto *TrueInst = dyn_cast<Instruction>(SI->getTrueValue());
@@ -322,8 +327,17 @@ bool PointerReplacer::collectUsers() {
if (!TrueInst || !FalseInst)
return false;
- UsersToReplace.insert(SI);
- PushUsersToWorklist(SI);
+ if (isAvailable(TrueInst) && isAvailable(FalseInst)) {
+ UsersToReplace.insert(SI);
+ PushUsersToWorklist(SI);
+ continue;
+ }
+
+ // Push select back onto the stack, followed by unavailable true/false
+ // value.
+ Worklist.emplace_back(SI);
+ if (!TryPushInstOperand(TrueInst) || !TryPushInstOperand(FalseInst))
+ return false;
} else if (auto *GEP = dyn_cast<GetElementPtrInst>(Inst)) {
UsersToReplace.insert(GEP);
PushUsersToWorklist(GEP);
diff --git a/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll b/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
new file mode 100644
index 0000000000000..921a72364e6f9
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
@@ -0,0 +1,20 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -mtriple=amdgcn-amd-amdhsa -passes=instcombine %s -S -o - | FileCheck %s
+
+; Crashed in IC PtrReplacer because an invalid select was generated with addrspace(4) and addrspace(5)
+; operands.
+
+define amdgpu_kernel void @eggs(ptr addrspace(4) byref([12 x i8]) align 16 %arg) {
+; CHECK-LABEL: define amdgpu_kernel void @eggs(
+; CHECK-SAME: ptr addrspace(4) byref([12 x i8]) align 16 [[ARG:%.*]]) {
+; CHECK-NEXT: [[BB:.*:]]
+; CHECK-NEXT: ret void
+;
+bb:
+ %alloca = alloca i32, i32 0, align 8, addrspace(5)
+ %alloca1 = alloca [12 x i8], align 16, addrspace(5)
+ call void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) %alloca1, ptr addrspace(4) %arg, i64 0, i1 false)
+ %select = select i1 false, ptr addrspace(5) %alloca1, ptr addrspace(5) %alloca
+ call void @llvm.memcpy.p0.p5.i64(ptr null, ptr addrspace(5) %select, i64 0, i1 false)
+ ret void
+}
>From 29cb1e3c782f6a2e089161d12dedf64b4841c0df Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Tue, 15 Jul 2025 14:27:01 +0200
Subject: [PATCH 2/3] test nits
---
.../ptr-replacer-select-addrspacecast-crash.ll | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll b/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
index 921a72364e6f9..f359447b6b9d8 100644
--- a/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
+++ b/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
@@ -1,5 +1,5 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt -mtriple=amdgcn-amd-amdhsa -passes=instcombine %s -S -o - | FileCheck %s
+; RUN: opt -S -mtriple=amdgcn-amd-amdhsa -passes=instcombine < %s | FileCheck %s
; Crashed in IC PtrReplacer because an invalid select was generated with addrspace(4) and addrspace(5)
; operands.
@@ -18,3 +18,18 @@ bb:
call void @llvm.memcpy.p0.p5.i64(ptr null, ptr addrspace(5) %select, i64 0, i1 false)
ret void
}
+
+define amdgpu_kernel void @milk(ptr addrspace(4) byref([12 x i8]) align 16 %arg) {
+; CHECK-LABEL: define amdgpu_kernel void @milk(
+; CHECK-SAME: ptr addrspace(4) byref([12 x i8]) align 16 [[ARG:%.*]]) {
+; CHECK-NEXT: [[BB:.*:]]
+; CHECK-NEXT: ret void
+;
+bb:
+ %alloca = alloca i32, i32 0, align 8, addrspace(5)
+ %alloca1 = alloca [12 x i8], align 16, addrspace(5)
+ call void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) %alloca1, ptr addrspace(4) %arg, i64 0, i1 false)
+ %select = select i1 false, ptr addrspace(5) %alloca, ptr addrspace(5) %alloca1
+ call void @llvm.memcpy.p0.p5.i64(ptr null, ptr addrspace(5) %select, i64 0, i1 false)
+ ret void
+}
>From 0a1bb70ce0939d870cb439285f73d9fa78a7bf36 Mon Sep 17 00:00:00 2001
From: pvanhout <pierre.vanhoutryve at amd.com>
Date: Wed, 16 Jul 2025 09:28:16 +0200
Subject: [PATCH 3/3] update test names, move them to ptr-replace-alloca.ll
---
.../InstCombine/AMDGPU/ptr-replace-alloca.ll | 33 +++++++++++++++++
...ptr-replacer-select-addrspacecast-crash.ll | 35 -------------------
2 files changed, 33 insertions(+), 35 deletions(-)
delete mode 100644 llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
diff --git a/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replace-alloca.ll b/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replace-alloca.ll
index 538cc19f9722e..beb84362b7f92 100644
--- a/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replace-alloca.ll
+++ b/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replace-alloca.ll
@@ -76,4 +76,37 @@ sink:
ret <2 x i64> %val.sink
}
+; Crashed in IC PtrReplacer because an invalid select was generated with addrspace(4) and addrspace(5)
+; operands.
+define amdgpu_kernel void @select_addr4_addr5(ptr addrspace(4) byref([12 x i8]) align 16 %arg) {
+; CHECK-LABEL: define amdgpu_kernel void @select_addr4_addr5(
+; CHECK-SAME: ptr addrspace(4) byref([12 x i8]) align 16 [[ARG:%.*]]) {
+; CHECK-NEXT: [[BB:.*:]]
+; CHECK-NEXT: ret void
+;
+bb:
+ %alloca = alloca i32, i32 0, align 8, addrspace(5)
+ %alloca1 = alloca [12 x i8], align 16, addrspace(5)
+ call void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) %alloca1, ptr addrspace(4) %arg, i64 0, i1 false)
+ %select = select i1 false, ptr addrspace(5) %alloca1, ptr addrspace(5) %alloca
+ call void @llvm.memcpy.p0.p5.i64(ptr null, ptr addrspace(5) %select, i64 0, i1 false)
+ ret void
+}
+
+; Same as above but with swapped operands on the select.
+define amdgpu_kernel void @select_addr4_addr5_swapped(ptr addrspace(4) byref([12 x i8]) align 16 %arg) {
+; CHECK-LABEL: define amdgpu_kernel void @select_addr4_addr5_swapped(
+; CHECK-SAME: ptr addrspace(4) byref([12 x i8]) align 16 [[ARG:%.*]]) {
+; CHECK-NEXT: [[BB:.*:]]
+; CHECK-NEXT: ret void
+;
+bb:
+ %alloca = alloca i32, i32 0, align 8, addrspace(5)
+ %alloca1 = alloca [12 x i8], align 16, addrspace(5)
+ call void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) %alloca1, ptr addrspace(4) %arg, i64 0, i1 false)
+ %select = select i1 false, ptr addrspace(5) %alloca, ptr addrspace(5) %alloca1
+ call void @llvm.memcpy.p0.p5.i64(ptr null, ptr addrspace(5) %select, i64 0, i1 false)
+ ret void
+}
+
declare void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) noalias writeonly captures(none), ptr addrspace(4) noalias readonly captures(none), i64, i1 immarg) #0
diff --git a/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll b/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
deleted file mode 100644
index f359447b6b9d8..0000000000000
--- a/llvm/test/Transforms/InstCombine/AMDGPU/ptr-replacer-select-addrspacecast-crash.ll
+++ /dev/null
@@ -1,35 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt -S -mtriple=amdgcn-amd-amdhsa -passes=instcombine < %s | FileCheck %s
-
-; Crashed in IC PtrReplacer because an invalid select was generated with addrspace(4) and addrspace(5)
-; operands.
-
-define amdgpu_kernel void @eggs(ptr addrspace(4) byref([12 x i8]) align 16 %arg) {
-; CHECK-LABEL: define amdgpu_kernel void @eggs(
-; CHECK-SAME: ptr addrspace(4) byref([12 x i8]) align 16 [[ARG:%.*]]) {
-; CHECK-NEXT: [[BB:.*:]]
-; CHECK-NEXT: ret void
-;
-bb:
- %alloca = alloca i32, i32 0, align 8, addrspace(5)
- %alloca1 = alloca [12 x i8], align 16, addrspace(5)
- call void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) %alloca1, ptr addrspace(4) %arg, i64 0, i1 false)
- %select = select i1 false, ptr addrspace(5) %alloca1, ptr addrspace(5) %alloca
- call void @llvm.memcpy.p0.p5.i64(ptr null, ptr addrspace(5) %select, i64 0, i1 false)
- ret void
-}
-
-define amdgpu_kernel void @milk(ptr addrspace(4) byref([12 x i8]) align 16 %arg) {
-; CHECK-LABEL: define amdgpu_kernel void @milk(
-; CHECK-SAME: ptr addrspace(4) byref([12 x i8]) align 16 [[ARG:%.*]]) {
-; CHECK-NEXT: [[BB:.*:]]
-; CHECK-NEXT: ret void
-;
-bb:
- %alloca = alloca i32, i32 0, align 8, addrspace(5)
- %alloca1 = alloca [12 x i8], align 16, addrspace(5)
- call void @llvm.memcpy.p5.p4.i64(ptr addrspace(5) %alloca1, ptr addrspace(4) %arg, i64 0, i1 false)
- %select = select i1 false, ptr addrspace(5) %alloca, ptr addrspace(5) %alloca1
- call void @llvm.memcpy.p0.p5.i64(ptr null, ptr addrspace(5) %select, i64 0, i1 false)
- ret void
-}
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