return passingValueIsAlwaysUndefined(V, GEP, PtrValueMayBeModified);
}
+ // Look through return.
+ if (ReturnInst *Ret = dyn_cast<ReturnInst>(Use)) {
+ bool HasNoUndefAttr =
+ Ret->getFunction()->hasRetAttribute(Attribute::NoUndef);
+ // Return undefined to a noundef return value is undefined.
+ if (isa<UndefValue>(C) && HasNoUndefAttr)
+ return true;
+ // Return null to a nonnull+noundef return value is undefined.
+ if (C->isNullValue() && HasNoUndefAttr &&
+ Ret->getFunction()->hasRetAttribute(Attribute::NonNull)) {
+ return !PtrValueMayBeModified;
+ }
+ }
+
// Look through bitcasts.
if (BitCastInst *BC = dyn_cast<BitCastInst>(Use))
return passingValueIsAlwaysUndefined(V, BC, PtrValueMayBeModified);
--- /dev/null
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S < %s | FileCheck %s
+
+define noundef i32 @test_ret_noundef(i1 %cond) {
+; CHECK-LABEL: @test_ret_noundef(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: ret i32 1
+;
+entry:
+ br i1 %cond, label %bb1, label %bb2
+
+bb1:
+ br label %bb2
+
+bb2:
+ %r = phi i32 [ undef, %entry ], [ 1, %bb1 ]
+ ret i32 %r
+}
+
+define i32 @test_ret(i1 %cond) {
+; CHECK-LABEL: @test_ret(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[COND:%.*]], i32 1, i32 undef
+; CHECK-NEXT: ret i32 [[SPEC_SELECT]]
+;
+entry:
+ br i1 %cond, label %bb1, label %bb2
+
+bb1:
+ br label %bb2
+
+bb2:
+ %r = phi i32 [ undef, %entry ], [ 1, %bb1 ]
+ ret i32 %r
+}
+
+define nonnull noundef ptr @test_ret_ptr_nonnull_noundef(i1 %cond, ptr %x) {
+; CHECK-LABEL: @test_ret_ptr_nonnull_noundef(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: call void @llvm.assume(i1 [[COND:%.*]])
+; CHECK-NEXT: ret ptr [[X:%.*]]
+;
+entry:
+ br i1 %cond, label %bb1, label %bb2
+
+bb1:
+ br label %bb2
+
+bb2:
+ %r = phi ptr [ null, %entry ], [ %x, %bb1 ]
+ ret ptr %r
+}
+
+define nonnull noundef ptr @test_ret_ptr_nonnull_noundef_gep_nonzero(i1 %cond, ptr %x) {
+; CHECK-LABEL: @test_ret_ptr_nonnull_noundef_gep_nonzero(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[COND:%.*]], ptr [[X:%.*]], ptr null
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds ptr, ptr [[SPEC_SELECT]], i64 12
+; CHECK-NEXT: ret ptr [[GEP]]
+;
+entry:
+ br i1 %cond, label %bb1, label %bb2
+
+bb1:
+ br label %bb2
+
+bb2:
+ %phi = phi ptr [ null, %entry ], [ %x, %bb1 ]
+ %gep = getelementptr inbounds ptr, ptr %phi, i64 12
+ ret ptr %gep
+}
+
+define nonnull ptr @test_ret_ptr_nonnull(i1 %cond, ptr %x) {
+; CHECK-LABEL: @test_ret_ptr_nonnull(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[COND:%.*]], ptr [[X:%.*]], ptr null
+; CHECK-NEXT: ret ptr [[SPEC_SELECT]]
+;
+entry:
+ br i1 %cond, label %bb1, label %bb2
+
+bb1:
+ br label %bb2
+
+bb2:
+ %r = phi ptr [ null, %entry ], [ %x, %bb1 ]
+ ret ptr %r
+}
+
+define noundef ptr @test_ret_ptr_noundef(i1 %cond, ptr %x) {
+; CHECK-LABEL: @test_ret_ptr_noundef(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[COND:%.*]], ptr [[X:%.*]], ptr null
+; CHECK-NEXT: ret ptr [[SPEC_SELECT]]
+;
+entry:
+ br i1 %cond, label %bb1, label %bb2
+
+bb1:
+ br label %bb2
+
+bb2:
+ %r = phi ptr [ null, %entry ], [ %x, %bb1 ]
+ ret ptr %r
+}
+
+define ptr @test_ret_ptr(i1 %cond, ptr %x) {
+; CHECK-LABEL: @test_ret_ptr(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[COND:%.*]], ptr [[X:%.*]], ptr null
+; CHECK-NEXT: ret ptr [[SPEC_SELECT]]
+;
+entry:
+ br i1 %cond, label %bb1, label %bb2
+
+bb1:
+ br label %bb2
+
+bb2:
+ %r = phi ptr [ null, %entry ], [ %x, %bb1 ]
+ ret ptr %r
+}