[llvm-branch-commits] [llvm] llvm-reduce: Fix asserting on TargetExtTypes that do not support zeroinit (PR #132733)

[Matt Arsenault via llvm-branch-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/132733

So far I've been unsuccessful in finding an example where the used constant
value is directly observed in the output. This avoids an assert in an intermediate
step of value replacement.

>From caedfd891a14f679e1f5f3d5f00f0e63d8599676 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 24 Mar 2025 19:52:11 +0700
Subject: [PATCH] llvm-reduce: Fix asserting on TargetExtTypes that do not
 support zeroinit

So far I've been unsuccessful in finding an example where the used constant
value is directly observed in the output. This avoids an assert in an intermediate
step of value replacement.
---
 .../operands-to-args-target-ext-type.ll       | 32 +++++++++++++++++++
 .../llvm-reduce/reduce-args-target-ext-ty.ll  | 13 ++++++++
 llvm/tools/llvm-reduce/deltas/Utils.cpp       | 11 ++++++-
 3 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/tools/llvm-reduce/operands-to-args-target-ext-type.ll
 create mode 100644 llvm/test/tools/llvm-reduce/reduce-args-target-ext-ty.ll

diff --git a/llvm/test/tools/llvm-reduce/operands-to-args-target-ext-type.ll b/llvm/test/tools/llvm-reduce/operands-to-args-target-ext-type.ll
new file mode 100644
index 0000000000000..cafd460f14ab3
--- /dev/null
+++ b/llvm/test/tools/llvm-reduce/operands-to-args-target-ext-type.ll
@@ -0,0 +1,32 @@
+; RUN: llvm-reduce %s -o %t --abort-on-invalid-reduction --delta-passes=operands-to-args --test FileCheck --test-arg %s --test-arg --check-prefixes=INTERESTING --test-arg --input-file
+; RUN: FileCheck %s --input-file %t --check-prefixes=RESULT
+
+; Make sure there's no assert from trying to create a
+; not-zeroinitializable target ext type
+
+
+declare void @uses_ext_ty(target("sometarget.sometype"))
+declare target("sometarget.sometype") @produces_ext_ty()
+
+; INTERESTING: define void @not_zero_foldable(
+
+; RESULT: define void @not_zero_foldable(target("sometarget.sometype") %call) {
+; RESULT-NEXT: %call1 = call target("sometarget.sometype") @produces_ext_ty()
+; RESULT-NEXT: call void @uses_ext_ty(target("sometarget.sometype") %call)
+define void @not_zero_foldable() {
+  %call = call target("sometarget.sometype") @produces_ext_ty()
+  call void @uses_ext_ty(target("sometarget.sometype") %call)
+  ret void
+}
+
+declare void @uses_zeroinit_ext_ty(target("spirv.zeroinit"))
+declare target("sometarget.sometype") @produces_zeroinit_ext_ty()
+
+; INTERESTING: define void @foldable_to_zero(
+; RESULT: define void @foldable_to_zero(target("spirv.zeroinit") %call) {
+define void @foldable_to_zero() {
+  %call = call target("spirv.zeroinit") @produces_zeroinit_ext_ty()
+  call void @uses_zeroinit_ext_ty(target("spirv.zeroinit") %call)
+  ret void
+}
+
diff --git a/llvm/test/tools/llvm-reduce/reduce-args-target-ext-ty.ll b/llvm/test/tools/llvm-reduce/reduce-args-target-ext-ty.ll
new file mode 100644
index 0000000000000..e3a7e80f5e4ef
--- /dev/null
+++ b/llvm/test/tools/llvm-reduce/reduce-args-target-ext-ty.ll
@@ -0,0 +1,13 @@
+; RUN: llvm-reduce %s -o %t --abort-on-invalid-reduction --delta-passes=arguments --test FileCheck --test-arg %s --test-arg --check-prefixes=INTERESTING --test-arg --input-file
+; RUN: FileCheck %s --input-file %t --check-prefixes=RESULT
+
+declare void @uses_ext_ty(target("sometarget.sometype"))
+declare target("sometarget.sometype") @produces_ext_ty()
+
+; INTERESTING: @interesting(
+; RESULT: @interesting(
+; RESULT: void @uses_ext_ty()
+define void @interesting(target("sometarget.sometype") %arg) {
+  call void @uses_ext_ty(target("sometarget.sometype") %arg)
+  ret void
+}
diff --git a/llvm/tools/llvm-reduce/deltas/Utils.cpp b/llvm/tools/llvm-reduce/deltas/Utils.cpp
index 669b9db8a825a..92a44921a7cfb 100644
--- a/llvm/tools/llvm-reduce/deltas/Utils.cpp
+++ b/llvm/tools/llvm-reduce/deltas/Utils.cpp
@@ -24,7 +24,16 @@ cl::opt<bool> llvm::Verbose("verbose",
                             cl::init(false), cl::cat(LLVMReduceOptions));
 
 Value *llvm::getDefaultValue(Type *T) {
-  return T->isVoidTy() ? PoisonValue::get(T) : Constant::getNullValue(T);
+  if (T->isVoidTy())
+    return PoisonValue::get(T);
+
+  if (auto *TET = dyn_cast<TargetExtType>(T)) {
+    if (TET->hasProperty(TargetExtType::HasZeroInit))
+      return ConstantTargetNone::get(TET);
+    return PoisonValue::get(TET);
+  }
+
+  return Constant::getNullValue(T);
 }
 
 bool llvm::hasAliasUse(Function &F) {