[GVN] Fix change reporting when removing assume (PR61574)

Report a change when removing a true/false assume.

Fixes llvm#61574.

Author: nikic

llvm/lib/Transforms/Scalar/GVN.cpp

@@ -1908,8 +1908,10 @@ bool GVNPass::processAssumeIntrinsic(AssumeInst *IntrinsicI) {
         MSSAU->insertDef(cast<MemoryDef>(NewDef), /*RenameUses=*/false);
       }
     }
-    if (isAssumeWithEmptyBundle(*IntrinsicI))
+    if (isAssumeWithEmptyBundle(*IntrinsicI)) {
       markInstructionForDeletion(IntrinsicI);
+      return true;
+    }
     return false;
   } else if (isa<Constant>(V)) {
     // If it's not false, and constant, it must evaluate to true. This means our

llvm/test/Transforms/GVN/assume.ll

@@ -1,9 +1,26 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -passes=gvn -S | FileCheck %s
+; RUN: opt < %s -passes=gvn -verify-analysis-invalidation -S | FileCheck %s
 
 declare void @llvm.assume(i1)
 declare void @use(i1)
 
+define void @assume_true() {
+; CHECK-LABEL: @assume_true(
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.assume(i1 true)
+  ret void
+}
+
+define void @assume_false() {
+; CHECK-LABEL: @assume_false(
+; CHECK-NEXT:    store i8 poison, ptr null, align 1
+; CHECK-NEXT:    ret void
+;
+  call void @llvm.assume(i1 false)
+  ret void
+}
+
 define void @assume_arg(i1 %x) {
 ; CHECK-LABEL: @assume_arg(
 ; CHECK-NEXT:    call void @llvm.assume(i1 [[X:%.*]])