From 7e337d8ba2ff5015d83f355be1049e3e13fa4d18 Mon Sep 17 00:00:00 2001
From: Max Kazantsev <mkazantsev@azul.com>
Date: Mon, 13 Sep 2021 15:27:33 +0700
Subject: [PATCH] [Test] Add more sophisticated tests for switch UB opt

Optimizer is being too smart with existing tests, and the transform
gets concealed by following transforms.
---
 llvm/test/Transforms/SimplifyCFG/switch_ub.ll | 130 ++++++++++++++++++
 1 file changed, 130 insertions(+)

diff --git a/llvm/test/Transforms/SimplifyCFG/switch_ub.ll b/llvm/test/Transforms/SimplifyCFG/switch_ub.ll
index d0d808897777..b9fcd54a5dfa 100644
--- a/llvm/test/Transforms/SimplifyCFG/switch_ub.ll
+++ b/llvm/test/Transforms/SimplifyCFG/switch_ub.ll
@@ -2,6 +2,10 @@
 ; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 ; RUN: opt < %s -passes=simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
+declare void @foo_01()
+declare void @foo_02()
+declare void @foo_03()
+
 ; TODO: Basing on fact that load(null) is UB, we can remove edge pred->bb.
 define i32 @test_01(i32* %p, i32 %x, i1 %cond) {
 ; CHECK-LABEL: @test_01(
@@ -73,3 +77,129 @@ bb:
 other_succ:
   ret i32 0
 }
+
+; TODO: Basing on fact that load(null) is UB, we can remove edge pred->bb.
+define i32 @test_03(i32* %p, i32 %x, i1 %cond) {
+; CHECK-LABEL: @test_03(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 [[COND:%.*]], label [[BB:%.*]], label [[PRED:%.*]]
+; CHECK:       pred:
+; CHECK-NEXT:    switch i32 [[X:%.*]], label [[BB]] [
+; CHECK-NEXT:    i32 42, label [[COMMON_RET:%.*]]
+; CHECK-NEXT:    i32 123456, label [[COMMON_RET]]
+; CHECK-NEXT:    i32 -654321, label [[COMMON_RET]]
+; CHECK-NEXT:    i32 1, label [[DO_1:%.*]]
+; CHECK-NEXT:    i32 2, label [[DO_2:%.*]]
+; CHECK-NEXT:    i32 3, label [[DO_3:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       common.ret:
+; CHECK-NEXT:    [[COMMON_RET_OP:%.*]] = phi i32 [ [[R:%.*]], [[BB]] ], [ 1, [[DO_1]] ], [ 1, [[DO_2]] ], [ 1, [[DO_3]] ], [ 0, [[PRED]] ], [ 0, [[PRED]] ], [ 0, [[PRED]] ]
+; CHECK-NEXT:    ret i32 [[COMMON_RET_OP]]
+; CHECK:       bb:
+; CHECK-NEXT:    [[PHI:%.*]] = phi i32* [ null, [[PRED]] ], [ [[P:%.*]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[R]] = load i32, i32* [[PHI]], align 4
+; CHECK-NEXT:    br label [[COMMON_RET]]
+; CHECK:       do_1:
+; CHECK-NEXT:    call void @foo_01()
+; CHECK-NEXT:    br label [[COMMON_RET]]
+; CHECK:       do_2:
+; CHECK-NEXT:    call void @foo_02()
+; CHECK-NEXT:    br label [[COMMON_RET]]
+; CHECK:       do_3:
+; CHECK-NEXT:    call void @foo_03()
+; CHECK-NEXT:    br label [[COMMON_RET]]
+;
+entry:
+  br i1 %cond, label %bb, label %pred
+
+pred:
+  switch i32 %x, label %bb [i32 42, label %other_succ
+  i32 123456, label %other_succ
+  i32 -654321, label %other_succ
+  i32 1, label %do_1
+  i32 2, label %do_2
+  i32 3, label %do_3]
+
+bb:
+  %phi = phi i32* [null, %pred], [%p, %entry]
+  %r = load i32, i32* %phi
+  ret i32 %r
+
+do_1:
+  call void @foo_01()
+  ret i32 1
+
+do_2:
+  call void @foo_02()
+  ret i32 1
+
+do_3:
+  call void @foo_03()
+  ret i32 1
+
+other_succ:
+  ret i32 0
+}
+
+; TODO: Basing on fact that load(null) is UB, we can remove edge pred->bb.
+define i32 @test_04(i32* %p, i32 %x, i1 %cond) {
+; CHECK-LABEL: @test_04(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 [[COND:%.*]], label [[BB:%.*]], label [[PRED:%.*]]
+; CHECK:       pred:
+; CHECK-NEXT:    switch i32 [[X:%.*]], label [[COMMON_RET:%.*]] [
+; CHECK-NEXT:    i32 42, label [[BB]]
+; CHECK-NEXT:    i32 123456, label [[BB]]
+; CHECK-NEXT:    i32 -654321, label [[BB]]
+; CHECK-NEXT:    i32 1, label [[DO_1:%.*]]
+; CHECK-NEXT:    i32 2, label [[DO_2:%.*]]
+; CHECK-NEXT:    i32 3, label [[DO_3:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       common.ret:
+; CHECK-NEXT:    [[COMMON_RET_OP:%.*]] = phi i32 [ [[R:%.*]], [[BB]] ], [ 1, [[DO_1]] ], [ 1, [[DO_2]] ], [ 1, [[DO_3]] ], [ 0, [[PRED]] ]
+; CHECK-NEXT:    ret i32 [[COMMON_RET_OP]]
+; CHECK:       bb:
+; CHECK-NEXT:    [[PHI:%.*]] = phi i32* [ null, [[PRED]] ], [ null, [[PRED]] ], [ null, [[PRED]] ], [ [[P:%.*]], [[ENTRY:%.*]] ]
+; CHECK-NEXT:    [[R]] = load i32, i32* [[PHI]], align 4
+; CHECK-NEXT:    br label [[COMMON_RET]]
+; CHECK:       do_1:
+; CHECK-NEXT:    call void @foo_01()
+; CHECK-NEXT:    br label [[COMMON_RET]]
+; CHECK:       do_2:
+; CHECK-NEXT:    call void @foo_02()
+; CHECK-NEXT:    br label [[COMMON_RET]]
+; CHECK:       do_3:
+; CHECK-NEXT:    call void @foo_03()
+; CHECK-NEXT:    br label [[COMMON_RET]]
+;
+entry:
+  br i1 %cond, label %bb, label %pred
+
+pred:
+  switch i32 %x, label %other_succ [i32 42, label %bb
+  i32 123456, label %bb
+  i32 -654321, label %bb
+  i32 1, label %do_1
+  i32 2, label %do_2
+  i32 3, label %do_3]
+
+bb:
+  %phi = phi i32* [null, %pred], [null, %pred], [null, %pred], [%p, %entry]
+  %r = load i32, i32* %phi
+  ret i32 %r
+
+do_1:
+  call void @foo_01()
+  ret i32 1
+
+do_2:
+  call void @foo_02()
+  ret i32 1
+
+do_3:
+  call void @foo_03()
+  ret i32 1
+
+other_succ:
+  ret i32 0
+}