From 7dfd0fb7f1cda3525d9c2fbdf680391b73479031 Mon Sep 17 00:00:00 2001
From: Roman Lebedev <lebedev.ri@gmail.com>
Date: Tue, 10 Sep 2019 13:29:40 +0000
Subject: [PATCH] [NFC][InstCombine] PR43251 - valid for other predicates too

llvm-svn: 371519
---
 .../result-of-usub-is-non-zero-and-no-overflow.ll  | 84 +++++++++++++++++++++-
 1 file changed, 82 insertions(+), 2 deletions(-)

diff --git a/llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll b/llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll
index d4b9066..b0206ec 100644
--- a/llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll
+++ b/llvm/test/Transforms/InstCombine/result-of-usub-is-non-zero-and-no-overflow.ll
@@ -54,6 +54,26 @@ define i1 @t1(i8 %base, i8 %offset) {
   %r = and i1 %not_null, %no_underflow
   ret i1 %r
 }
+define i1 @t1_strict(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t1_strict(
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ugt i8 [[BASE]], [[OFFSET]]
+; CHECK-NEXT:    call void @use1(i1 [[NO_UNDERFLOW]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    call void @use1(i1 [[NOT_NULL]])
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %adjusted = sub i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %no_underflow = icmp ugt i8 %base, %offset ; same is valid for strict predicate
+  call void @use1(i1 %no_underflow)
+  %not_null = icmp ne i8 %adjusted, 0
+  call void @use1(i1 %not_null)
+  %r = and i1 %not_null, %no_underflow
+  ret i1 %r
+}
 
 define i1 @t2(i8 %base, i8 %offset) {
 ; CHECK-LABEL: @t2(
@@ -117,7 +137,7 @@ define i1 @t4_commutability1(i8 %base, i8 %offset) {
 ;
   %adjusted = sub i8 %base, %offset
   call void @use8(i8 %adjusted)
-  %no_underflow = icmp uge i8 %base, %offset ; swapped
+  %no_underflow = icmp uge i8 %base, %offset
   call void @use1(i1 %no_underflow)
   %not_null = icmp ne i8 %adjusted, 0
   call void @use1(i1 %not_null)
@@ -188,7 +208,27 @@ define i1 @t7(i8 %base, i8 %offset) {
 ;
   %adjusted = sub i8 %base, %offset
   call void @use8(i8 %adjusted)
-  %underflow = icmp ugt i8 %adjusted, %base
+  %underflow = icmp ult i8 %base, %offset
+  call void @use1(i1 %underflow)
+  %null = icmp eq i8 %adjusted, 0
+  call void @use1(i1 %null)
+  %r = or i1 %null, %underflow
+  ret i1 %r
+}
+define i1 @t7_nonstrict(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t7_nonstrict(
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[UNDERFLOW:%.*]] = icmp ule i8 [[BASE]], [[OFFSET]]
+; CHECK-NEXT:    call void @use1(i1 [[UNDERFLOW]])
+; CHECK-NEXT:    [[NULL:%.*]] = icmp eq i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    call void @use1(i1 [[NULL]])
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[NULL]], [[UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %adjusted = sub i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %underflow = icmp ule i8 %base, %offset ; same is valid for non-strict predicate
   call void @use1(i1 %underflow)
   %null = icmp eq i8 %adjusted, 0
   call void @use1(i1 %null)
@@ -267,6 +307,26 @@ define i1 @t10(i8 %base, i8 %offset) {
   %r = or i1 %not_null, %no_underflow
   ret i1 %r
 }
+define i1 @t10_strict_bad(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t10_strict_bad(
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[NO_UNDERFLOW:%.*]] = icmp ugt i8 [[BASE]], [[OFFSET]]
+; CHECK-NEXT:    call void @use1(i1 [[NO_UNDERFLOW]])
+; CHECK-NEXT:    [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    call void @use1(i1 [[NOT_NULL]])
+; CHECK-NEXT:    [[R:%.*]] = or i1 [[NOT_NULL]], [[NO_UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %adjusted = sub i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %no_underflow = icmp ugt i8 %base, %offset ; but not for non-strict predicate
+  call void @use1(i1 %no_underflow)
+  %not_null = icmp ne i8 %adjusted, 0
+  call void @use1(i1 %not_null)
+  %r = or i1 %not_null, %no_underflow
+  ret i1 %r
+}
 
 define i1 @t11(i8 %base, i8 %offset) {
 ; CHECK-LABEL: @t11(
@@ -318,6 +378,26 @@ define i1 @t12(i8 %base, i8 %offset) {
   %r = and i1 %null, %underflow
   ret i1 %r
 }
+define i1 @t12_nonstrict_bad(i8 %base, i8 %offset) {
+; CHECK-LABEL: @t12_nonstrict_bad(
+; CHECK-NEXT:    [[ADJUSTED:%.*]] = sub i8 [[BASE:%.*]], [[OFFSET:%.*]]
+; CHECK-NEXT:    call void @use8(i8 [[ADJUSTED]])
+; CHECK-NEXT:    [[UNDERFLOW:%.*]] = icmp uge i8 [[ADJUSTED]], [[BASE]]
+; CHECK-NEXT:    call void @use1(i1 [[UNDERFLOW]])
+; CHECK-NEXT:    [[NULL:%.*]] = icmp eq i8 [[ADJUSTED]], 0
+; CHECK-NEXT:    call void @use1(i1 [[NULL]])
+; CHECK-NEXT:    [[R:%.*]] = and i1 [[NULL]], [[UNDERFLOW]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %adjusted = sub i8 %base, %offset
+  call void @use8(i8 %adjusted)
+  %underflow = icmp uge i8 %adjusted, %base ; but not for non-strict predicate
+  call void @use1(i1 %underflow)
+  %null = icmp eq i8 %adjusted, 0
+  call void @use1(i1 %null)
+  %r = and i1 %null, %underflow
+  ret i1 %r
+}
 
 define i1 @t13(i8 %base, i8 %offset) {
 ; CHECK-LABEL: @t13(
-- 
2.7.4