[llvm] [SimplifyCFG] Switch to use `paramHasNonNullAttr` (PR #125383)
Yingwei Zheng via llvm-commits
llvm-commits at lists.llvm.org
Sun Jun 1 09:06:10 PDT 2025
https://github.com/dtcxzyw updated https://github.com/llvm/llvm-project/pull/125383
>From 5b59246712a5c9446a526503818b7f86b824f03c Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Sun, 2 Feb 2025 13:28:49 +0800
Subject: [PATCH 1/2] [SimplifyCFG] Switch to use `paramHasNonNullAttr`
---
llvm/include/llvm/IR/InstrTypes.h | 12 ++++++++++--
llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 4 ++--
.../Transforms/SimplifyCFG/UnreachableEliminate.ll | 11 +++++------
3 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/llvm/include/llvm/IR/InstrTypes.h b/llvm/include/llvm/IR/InstrTypes.h
index 8e47e3c7b3a7c..61070aa79b15d 100644
--- a/llvm/include/llvm/IR/InstrTypes.h
+++ b/llvm/include/llvm/IR/InstrTypes.h
@@ -1839,7 +1839,11 @@ class CallBase : public Instruction {
/// Extract the number of dereferenceable bytes for a call or
/// parameter (0=unknown).
uint64_t getParamDereferenceableBytes(unsigned i) const {
- return Attrs.getParamDereferenceableBytes(i);
+ uint64_t Bytes = Attrs.getParamDereferenceableBytes(i);
+ if (const Function *F = getCalledFunction())
+ Bytes =
+ std::max(Bytes, F->getAttributes().getParamDereferenceableBytes(i));
+ return Bytes;
}
/// Extract the number of dereferenceable_or_null bytes for a call
@@ -1857,7 +1861,11 @@ class CallBase : public Instruction {
/// Extract the number of dereferenceable_or_null bytes for a
/// parameter (0=unknown).
uint64_t getParamDereferenceableOrNullBytes(unsigned i) const {
- return Attrs.getParamDereferenceableOrNullBytes(i);
+ uint64_t Bytes = Attrs.getParamDereferenceableOrNullBytes(i);
+ if (const Function *F = getCalledFunction())
+ Bytes = std::max(
+ Bytes, F->getAttributes().getParamDereferenceableOrNullBytes(i));
+ return Bytes;
}
/// Extract a test mask for disallowed floating-point value classes for the
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 7840601d341b8..b7299e01b0c5f 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -8224,8 +8224,8 @@ static bool passingValueIsAlwaysUndefined(Value *V, Instruction *I, bool PtrValu
if (CB->isArgOperand(&Use)) {
unsigned ArgIdx = CB->getArgOperandNo(&Use);
// Passing null to a nonnnull+noundef argument is undefined.
- if (C->isNullValue() && CB->isPassingUndefUB(ArgIdx) &&
- CB->paramHasAttr(ArgIdx, Attribute::NonNull))
+ if (isa<ConstantPointerNull>(C) &&
+ CB->paramHasNonNullAttr(ArgIdx, /*AllowUndefOrPoison=*/false))
return !PtrValueMayBeModified;
// Passing undef to a noundef argument is undefined.
if (isa<UndefValue>(C) && CB->isPassingUndefUB(ArgIdx))
diff --git a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
index aae1ab032f36e..2da5d18b63f49 100644
--- a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
+++ b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
@@ -238,7 +238,7 @@ else:
}
declare ptr @fn_nonnull_noundef_arg(ptr nonnull noundef %p)
-declare ptr @fn_nonnull_deref_arg(ptr nonnull dereferenceable(4) %p)
+declare ptr @fn_deref_arg(ptr dereferenceable(4) %p)
declare ptr @fn_nonnull_deref_or_null_arg(ptr nonnull dereferenceable_or_null(4) %p)
declare ptr @fn_nonnull_arg(ptr nonnull %p)
declare ptr @fn_noundef_arg(ptr noundef %p)
@@ -271,7 +271,7 @@ define void @test9_deref(i1 %X, ptr %Y) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = xor i1 [[X:%.*]], true
; CHECK-NEXT: call void @llvm.assume(i1 [[TMP0]])
-; CHECK-NEXT: [[TMP1:%.*]] = call ptr @fn_nonnull_deref_arg(ptr [[Y:%.*]])
+; CHECK-NEXT: [[TMP1:%.*]] = call ptr @fn_deref_arg(ptr [[Y:%.*]])
; CHECK-NEXT: ret void
;
entry:
@@ -282,7 +282,7 @@ if:
else:
%phi = phi ptr [ %Y, %entry ], [ null, %if ]
- call ptr @fn_nonnull_deref_arg(ptr %phi)
+ call ptr @fn_deref_arg(ptr %phi)
ret void
}
@@ -290,9 +290,8 @@ else:
define void @test9_deref_or_null(i1 %X, ptr %Y) {
; CHECK-LABEL: @test9_deref_or_null(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[TMP0:%.*]] = xor i1 [[X:%.*]], true
-; CHECK-NEXT: call void @llvm.assume(i1 [[TMP0]])
-; CHECK-NEXT: [[TMP1:%.*]] = call ptr @fn_nonnull_deref_or_null_arg(ptr [[Y:%.*]])
+; CHECK-NEXT: [[Y:%.*]] = select i1 [[X:%.*]], ptr null, ptr [[Y1:%.*]]
+; CHECK-NEXT: [[TMP1:%.*]] = call ptr @fn_nonnull_deref_or_null_arg(ptr [[Y]])
; CHECK-NEXT: ret void
;
entry:
>From 49bc007c3efb6c0dc40b252741e8fe7c043a793e Mon Sep 17 00:00:00 2001
From: Yingwei Zheng <dtcxzyw2333 at gmail.com>
Date: Mon, 2 Jun 2025 00:05:49 +0800
Subject: [PATCH 2/2] [IR] Only check attributes
---
llvm/include/llvm/IR/InstrTypes.h | 12 ++----------
llvm/lib/IR/Instructions.cpp | 2 +-
2 files changed, 3 insertions(+), 11 deletions(-)
diff --git a/llvm/include/llvm/IR/InstrTypes.h b/llvm/include/llvm/IR/InstrTypes.h
index 61070aa79b15d..8e47e3c7b3a7c 100644
--- a/llvm/include/llvm/IR/InstrTypes.h
+++ b/llvm/include/llvm/IR/InstrTypes.h
@@ -1839,11 +1839,7 @@ class CallBase : public Instruction {
/// Extract the number of dereferenceable bytes for a call or
/// parameter (0=unknown).
uint64_t getParamDereferenceableBytes(unsigned i) const {
- uint64_t Bytes = Attrs.getParamDereferenceableBytes(i);
- if (const Function *F = getCalledFunction())
- Bytes =
- std::max(Bytes, F->getAttributes().getParamDereferenceableBytes(i));
- return Bytes;
+ return Attrs.getParamDereferenceableBytes(i);
}
/// Extract the number of dereferenceable_or_null bytes for a call
@@ -1861,11 +1857,7 @@ class CallBase : public Instruction {
/// Extract the number of dereferenceable_or_null bytes for a
/// parameter (0=unknown).
uint64_t getParamDereferenceableOrNullBytes(unsigned i) const {
- uint64_t Bytes = Attrs.getParamDereferenceableOrNullBytes(i);
- if (const Function *F = getCalledFunction())
- Bytes = std::max(
- Bytes, F->getAttributes().getParamDereferenceableOrNullBytes(i));
- return Bytes;
+ return Attrs.getParamDereferenceableOrNullBytes(i);
}
/// Extract a test mask for disallowed floating-point value classes for the
diff --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index f404e11b9c0f0..e22b04e1bb0b3 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -448,7 +448,7 @@ bool CallBase::paramHasNonNullAttr(unsigned ArgNo,
(AllowUndefOrPoison || paramHasAttr(ArgNo, Attribute::NoUndef)))
return true;
- if (getParamDereferenceableBytes(ArgNo) > 0 &&
+ if (paramHasAttr(ArgNo, Attribute::Dereferenceable) &&
!NullPointerIsDefined(
getCaller(),
getArgOperand(ArgNo)->getType()->getPointerAddressSpace()))
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