Users.emplace_back(I);
continue;
}
+
+ if (isReallocLikeFn(I, TLI, true)) {
+ Users.emplace_back(I);
+ Worklist.push_back(I);
+ continue;
+ }
+
return false;
case Instruction::Store: {
if (isa<ConstantPointerNull>(Op))
return eraseInstFromFunction(FI);
+ // If we had free(realloc(...)) with no intervening uses, then eliminate the
+ // realloc() entirely.
+ if (CallInst *CI = dyn_cast<CallInst>(Op)) {
+ if (CI->hasOneUse() && isReallocLikeFn(CI, &TLI, true)) {
+ return eraseInstFromFunction(
+ *replaceInstUsesWith(*CI, CI->getOperand(0)));
+ }
+ }
+
// If we optimize for code size, try to move the call to free before the null
// test so that simplify cfg can remove the empty block and dead code
// elimination the branch. I.e., helps to turn something like:
--- /dev/null
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --scrub-attributes
+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+define dso_local void @test() local_unnamed_addr #0 {
+; CHECK-LABEL: @test(
+; CHECK-NEXT: ret void
+;
+ %1 = tail call noalias align 16 dereferenceable_or_null(4) i8* @malloc(i64 4) #4
+ %2 = tail call align 16 dereferenceable_or_null(6) i8* @realloc(i8* %1, i64 6) #4
+ tail call void @free(i8* %2) #4
+ ret void
+}
+
+declare dso_local noalias noundef i8* @malloc(i64 noundef) local_unnamed_addr #1
+declare dso_local noalias noundef i8* @realloc(i8* nocapture, i64 noundef) local_unnamed_addr #2
+declare dso_local void @free(i8* nocapture noundef) local_unnamed_addr #2
+declare void @llvm.dbg.value(metadata, metadata, metadata) #3
+
+attributes #0 = { mustprogress nounwind uwtable willreturn }
+attributes #1 = { inaccessiblememonly mustprogress nofree nounwind willreturn }
+attributes #2 = { inaccessiblemem_or_argmemonly mustprogress nounwind willreturn }
+attributes #3 = { nofree nosync nounwind readnone speculatable willreturn }
+attributes #4 = { nounwind }
+
--- /dev/null
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --scrub-attributes
+; RUN: opt -S -instcombine < %s | FileCheck %s
+
+define dso_local void @_Z3fooPv(i8* nocapture %0) local_unnamed_addr #0 {
+; CHECK-LABEL: @_Z3fooPv(
+; CHECK-NEXT: tail call void @free(i8* [[TMP0:%.*]])
+; CHECK-NEXT: ret void
+;
+ %2 = tail call align 16 dereferenceable_or_null(6) i8* @realloc(i8* %0, i64 6) #2
+ tail call void @free(i8* %2) #2
+ ret void
+}
+
+declare dso_local noalias noundef i8* @realloc(i8* nocapture, i64 noundef) local_unnamed_addr #1
+declare dso_local void @free(i8* nocapture noundef) local_unnamed_addr #1
+
+attributes #0 = { mustprogress nounwind uwtable willreturn }
+attributes #1 = { inaccessiblemem_or_argmemonly mustprogress nounwind willreturn }
+attributes #2 = { nounwind }