[GlobalOpt] Check if users are CallBase when changing CC #161399
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@llvm/pr-subscribers-llvm-transforms Author: Hongyu Chen (XChy) ChangesFixes #156656 Full diff: https://github.com/llvm/llvm-project/pull/161399.diff 2 Files Affected:
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index f88d51f443bcf..c5a13c83ab39b 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1680,7 +1680,8 @@ processGlobal(GlobalValue &GV,
/// FastCC.
static void ChangeCalleesToFastCall(Function *F) {
for (User *U : F->users())
- cast<CallBase>(U)->setCallingConv(CallingConv::Fast);
+ if (auto *Call = dyn_cast<CallBase>(U))
+ Call->setCallingConv(CallingConv::Fast);
}
static AttributeList StripAttr(LLVMContext &C, AttributeList Attrs,
@@ -1779,7 +1780,8 @@ isValidCandidateForColdCC(Function &F,
static void changeCallSitesToColdCC(Function *F) {
for (User *U : F->users())
- cast<CallBase>(U)->setCallingConv(CallingConv::Cold);
+ if (auto *Call = dyn_cast<CallBase>(U))
+ Call->setCallingConv(CallingConv::Cold);
}
// This function iterates over all the call instructions in the input Function
diff --git a/llvm/test/Transforms/GlobalOpt/fastcc.ll b/llvm/test/Transforms/GlobalOpt/fastcc.ll
index 854357e6fad97..f63cf64ca2f11 100644
--- a/llvm/test/Transforms/GlobalOpt/fastcc.ll
+++ b/llvm/test/Transforms/GlobalOpt/fastcc.ll
@@ -1,16 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt < %s -passes=globalopt -S | FileCheck %s
declare token @llvm.call.preallocated.setup(i32)
declare ptr @llvm.call.preallocated.arg(token, i32)
define internal i32 @f(ptr %m) {
-; CHECK-LABEL: define internal fastcc i32 @f
+; CHECK-LABEL: define internal fastcc i32 @f(
+; CHECK-SAME: ptr [[M:%.*]]) unnamed_addr {
+; CHECK-NEXT: [[V:%.*]] = load i32, ptr [[M]], align 4
+; CHECK-NEXT: ret i32 [[V]]
+;
%v = load i32, ptr %m
ret i32 %v
}
define internal x86_thiscallcc i32 @g(ptr %m) {
-; CHECK-LABEL: define internal fastcc i32 @g
+; CHECK-LABEL: define internal fastcc i32 @g(
+; CHECK-SAME: ptr [[M:%.*]]) unnamed_addr {
+; CHECK-NEXT: [[V:%.*]] = load i32, ptr [[M]], align 4
+; CHECK-NEXT: ret i32 [[V]]
+;
%v = load i32, ptr %m
ret i32 %v
}
@@ -18,41 +27,80 @@ define internal x86_thiscallcc i32 @g(ptr %m) {
; Leave this one alone, because the user went out of their way to request this
; convention.
define internal coldcc i32 @h(ptr %m) {
-; CHECK-LABEL: define internal coldcc i32 @h
+; CHECK-LABEL: define internal coldcc i32 @h(
+; CHECK-SAME: ptr [[M:%.*]]) unnamed_addr {
+; CHECK-NEXT: [[V:%.*]] = load i32, ptr [[M]], align 4
+; CHECK-NEXT: ret i32 [[V]]
+;
%v = load i32, ptr %m
ret i32 %v
}
define internal i32 @j(ptr %m) {
-; CHECK-LABEL: define internal i32 @j
+; CHECK-LABEL: define internal i32 @j(
+; CHECK-SAME: ptr [[M:%.*]]) {
+; CHECK-NEXT: [[V:%.*]] = load i32, ptr [[M]], align 4
+; CHECK-NEXT: ret i32 [[V]]
+;
%v = load i32, ptr %m
ret i32 %v
}
define internal i32 @inalloca(ptr inalloca(i32) %p) {
-; CHECK-LABEL: define internal fastcc i32 @inalloca(ptr %p)
+; CHECK-LABEL: define internal fastcc i32 @inalloca(
+; CHECK-SAME: ptr [[P:%.*]]) unnamed_addr {
+; CHECK-NEXT: [[RV:%.*]] = load i32, ptr [[P]], align 4
+; CHECK-NEXT: ret i32 [[RV]]
+;
%rv = load i32, ptr %p
ret i32 %rv
}
define i32 @inalloca2_caller(ptr inalloca(i32) %p) {
+; CHECK-LABEL: define i32 @inalloca2_caller(
+; CHECK-SAME: ptr inalloca(i32) [[P:%.*]]) local_unnamed_addr {
+; CHECK-NEXT: [[RV:%.*]] = musttail call i32 @inalloca2(ptr inalloca(i32) [[P]])
+; CHECK-NEXT: ret i32 [[RV]]
+;
%rv = musttail call i32 @inalloca2(ptr inalloca(i32) %p)
ret i32 %rv
}
define internal i32 @inalloca2(ptr inalloca(i32) %p) {
; Because of the musttail caller, this inalloca cannot be dropped.
-; CHECK-LABEL: define internal i32 @inalloca2(ptr inalloca(i32) %p)
+; CHECK-LABEL: define internal i32 @inalloca2(
+; CHECK-SAME: ptr inalloca(i32) [[P:%.*]]) unnamed_addr {
+; CHECK-NEXT: [[RV:%.*]] = load i32, ptr [[P]], align 4
+; CHECK-NEXT: ret i32 [[RV]]
+;
%rv = load i32, ptr %p
ret i32 %rv
}
define internal i32 @preallocated(ptr preallocated(i32) %p) {
-; CHECK-LABEL: define internal fastcc i32 @preallocated(ptr %p)
+; CHECK-LABEL: define internal fastcc i32 @preallocated(
+; CHECK-SAME: ptr [[P:%.*]]) unnamed_addr {
+; CHECK-NEXT: [[RV:%.*]] = load i32, ptr [[P]], align 4
+; CHECK-NEXT: ret i32 [[RV]]
+;
%rv = load i32, ptr %p
ret i32 %rv
}
define void @call_things() {
+; CHECK-LABEL: define void @call_things() local_unnamed_addr {
+; CHECK-NEXT: [[M:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[TMP1:%.*]] = call fastcc i32 @f(ptr [[M]])
+; CHECK-NEXT: [[TMP2:%.*]] = call fastcc i32 @g(ptr [[M]])
+; CHECK-NEXT: [[TMP3:%.*]] = call coldcc i32 @h(ptr [[M]])
+; CHECK-NEXT: [[TMP4:%.*]] = call i32 @j(ptr [[M]])
+; CHECK-NEXT: [[ARGS:%.*]] = alloca inalloca i32, align 4
+; CHECK-NEXT: [[TMP5:%.*]] = call fastcc i32 @inalloca(ptr [[ARGS]])
+; CHECK-NEXT: [[TMP6:%.*]] = call ptr @llvm.stacksave.p0()
+; CHECK-NEXT: [[PAARG:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[TMP7:%.*]] = call fastcc i32 @preallocated(ptr [[PAARG]])
+; CHECK-NEXT: call void @llvm.stackrestore.p0(ptr [[TMP6]])
+; CHECK-NEXT: ret void
+;
%m = alloca i32
call i32 @f(ptr %m)
call x86_thiscallcc i32 @g(ptr %m)
@@ -65,15 +113,16 @@ define void @call_things() {
call i32 @preallocated(ptr preallocated(i32) %N) ["preallocated"(token %c)]
ret void
}
-; CHECK-LABEL: define void @call_things()
-; CHECK: call fastcc i32 @f
-; CHECK: call fastcc i32 @g
-; CHECK: call coldcc i32 @h
-; CHECK: call i32 @j
-; CHECK: call fastcc i32 @inalloca(ptr %args)
-; CHECK-NOT: llvm.call.preallocated
-; CHECK: call fastcc i32 @preallocated(ptr %paarg)
@llvm.used = appending global [1 x ptr] [
- ptr @j
+ ptr @j
], section "llvm.metadata"
+
+define internal i32 @constexpr_self_user() addrspace(1) {
+; CHECK-LABEL: define internal fastcc i32 @constexpr_self_user() addrspace(1) {
+; CHECK-NEXT: [[OBJSIZE:%.*]] = call i32 @llvm.objectsize.i32.p0(ptr addrspacecast (ptr addrspace(1) @constexpr_self_user to ptr), i1 false, i1 false, i1 false)
+; CHECK-NEXT: ret i32 [[OBJSIZE]]
+;
+ %objsize = call i32 @llvm.objectsize.i32.p0(ptr addrspacecast (ptr addrspace(1) @constexpr_self_user to ptr), i1 false, i1 false, i1 false)
+ ret i32 %objsize
+}
|
nikic
approved these changes
Sep 30, 2025
| ], section "llvm.metadata" | ||
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| define internal i32 @constexpr_self_user() addrspace(1) { |
There was a problem hiding this comment.
Remove the address space, assuming it's not relevant somehow?
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It's only reproducible with addrspacecast. See also https://godbolt.org/z/qcfY8z91G.
My description is not clear. Actually, hasChangeableCCImpl ignores assume-like calls with addrspacecast.
But we try to cast addrspacecast to CallBase later.
There was a problem hiding this comment.
Ah, but that indicates another issue now. We'll also ignore assume-like calls directly:
llvm-project/llvm/lib/IR/Function.cpp
Lines 995 to 999 in 3c0f7b1
But in that case we're going to change the CC on the assume-like call, not on a call to the function. So I think the code needs to check that it's the callee operand.
There was a problem hiding this comment.
Thanks, I missed it. Fix it now.
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Oct 3, 2025
Fixes llvm#156656 `hasChangeableCCImpl` guarantees the address of the function is not taken, but it ignores assume-like calls. This patch ignores assume-like calls when changing CC.
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Fixes #156656
hasChangeableCCImplguarantees the address of the function is not taken, but it ignores assume-like calls.This patch ignores assume-like calls when changing CC.