[llvm] 129a354 - [WebAssemblyOptimizeReturned] Skip lifetime intrinsic uses

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2025-07-25T12:12:26+02:00
New Revision: 129a35454ccb1d535b6cdd5cc768ab0b2897f889

URL: https://github.com/llvm/llvm-project/commit/129a35454ccb1d535b6cdd5cc768ab0b2897f889
DIFF: https://github.com/llvm/llvm-project/commit/129a35454ccb1d535b6cdd5cc768ab0b2897f889.diff

LOG: [WebAssemblyOptimizeReturned] Skip lifetime intrinsic uses

Replacing an alloca with a call result in a lifetime intrinsic
will cause a verifier error.

Fixes https://github.com/llvm/llvm-project/issues/150498.

Added: 
    

Modified: 
    llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp
    llvm/test/CodeGen/WebAssembly/returned.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp
index 7912aeb4f5029..ffd135d62aaf0 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyOptimizeReturned.cpp
@@ -63,8 +63,10 @@ void OptimizeReturned::visitCallBase(CallBase &CB) {
       if (isa<Constant>(Arg))
         continue;
       // Like replaceDominatedUsesWith but using Instruction/Use dominance.
-      Arg->replaceUsesWithIf(&CB,
-                             [&](Use &U) { return DT->dominates(&CB, U); });
+      Arg->replaceUsesWithIf(&CB, [&](Use &U) {
+        auto *I = cast<Instruction>(U.getUser());
+        return !I->isLifetimeStartOrEnd() && DT->dominates(&CB, U);
+      });
     }
 }
 

diff  --git a/llvm/test/CodeGen/WebAssembly/returned.ll b/llvm/test/CodeGen/WebAssembly/returned.ll
index e767e29704d54..aef75d8bee437 100644
--- a/llvm/test/CodeGen/WebAssembly/returned.ll
+++ b/llvm/test/CodeGen/WebAssembly/returned.ll
@@ -80,3 +80,27 @@ define i32 @test_second_arg(i32 %a, i32 %b) {
     %call = call i32 @do_something_else(i32 %a, i32 %b)
     ret i32 %b
 }
+
+define void @test() {
+; CHECK-LABEL: test:
+; CHECK:         .functype test () -> ()
+; CHECK-NEXT:  # %bb.0: # %entry
+; CHECK-NEXT:    global.get $push0=, __stack_pointer
+; CHECK-NEXT:    i32.const $push1=, 16
+; CHECK-NEXT:    i32.sub $push7=, $pop0, $pop1
+; CHECK-NEXT:    local.tee $push6=, $0=, $pop7
+; CHECK-NEXT:    global.set __stack_pointer, $pop6
+; CHECK-NEXT:    i32.const $push4=, 12
+; CHECK-NEXT:    i32.add $push5=, $0, $pop4
+; CHECK-NEXT:    call $drop=, returns_arg, $pop5
+; CHECK-NEXT:    i32.const $push2=, 16
+; CHECK-NEXT:    i32.add $push3=, $0, $pop2
+; CHECK-NEXT:    global.set __stack_pointer, $pop3
+; CHECK-NEXT:    return
+entry:
+  %a = alloca i32
+  call void @llvm.lifetime.start.p0(i64 4, ptr %a)
+  %ret = call ptr @returns_arg(ptr %a)
+  call void @llvm.lifetime.end.p0(i64 4, ptr %a)
+  ret void
+}