From 5369775a848db9840c52951dcc86ffe3a7db3616 Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Tue, 6 Dec 2016 22:09:52 +0000
Subject: [PATCH] [InstSimplify] fixed (?) to not mutate icmps

As Eli noted in the post-commit thread for r288833, the use of
swapOperands() may not be allowed in InstSimplify, so I'm
removing those calls here pending further review.

The swap mutates the icmp, and there doesn't appear to be precedent
for instruction mutation in InstSimplify.

I didn't actually have any tests for those cases, so I'm adding
a few here.

llvm-svn: 288855
---
 llvm/lib/Analysis/InstructionSimplify.cpp          | 14 ++++--------
 .../Transforms/InstSimplify/and-icmps-same-ops.ll  | 26 ++++++++++++++++++++++
 .../Transforms/InstSimplify/or-icmps-same-ops.ll   | 26 ++++++++++++++++++++++
 3 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index cc4a6ba..bbabf2a 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1523,11 +1523,8 @@ static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
 static Value *simplifyAndOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) {
   ICmpInst::Predicate Pred0, Pred1;
   Value *A ,*B;
-  match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B)));
-  if (match(Op1, m_ICmp(Pred1, m_Specific(B), m_Specific(A))))
-    Op1->swapOperands();
-
-  if (!match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
+  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
+      !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
     return nullptr;
 
   // We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
@@ -1738,11 +1735,8 @@ Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const DataLayout &DL,
 static Value *simplifyOrOfICmpsWithSameOperands(ICmpInst *Op0, ICmpInst *Op1) {
   ICmpInst::Predicate Pred0, Pred1;
   Value *A ,*B;
-  match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B)));
-  if (match(Op1, m_ICmp(Pred1, m_Specific(B), m_Specific(A))))
-    Op1->swapOperands();
-
-  if (!match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
+  if (!match(Op0, m_ICmp(Pred0, m_Value(A), m_Value(B))) ||
+      !match(Op1, m_ICmp(Pred1, m_Specific(A), m_Specific(B))))
     return nullptr;
 
   // We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
diff --git a/llvm/test/Transforms/InstSimplify/and-icmps-same-ops.ll b/llvm/test/Transforms/InstSimplify/and-icmps-same-ops.ll
index 8a665c3..4da7938 100644
--- a/llvm/test/Transforms/InstSimplify/and-icmps-same-ops.ll
+++ b/llvm/test/Transforms/InstSimplify/and-icmps-same-ops.ll
@@ -1211,3 +1211,29 @@ define <2 x i1> @ult_ule_vec(<2 x i8> %a, <2 x i8> %b) {
   ret <2 x i1> %and
 }
 
+define i1 @ult_uge_swap(i8 %a, i8 %b) {
+; CHECK-LABEL: @ult_uge_swap(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i8 %a, %b
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp uge i8 %b, %a
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[CMP1]], [[CMP2]]
+; CHECK-NEXT:    ret i1 [[AND]]
+;
+  %cmp1 = icmp ult i8 %a, %b
+  %cmp2 = icmp uge i8 %b, %a
+  %and = and i1 %cmp1, %cmp2
+  ret i1 %and
+}
+
+define i1 @ult_ult_swap(i8 %a, i8 %b) {
+; CHECK-LABEL: @ult_ult_swap(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i8 %a, %b
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ult i8 %b, %a
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[CMP1]], [[CMP2]]
+; CHECK-NEXT:    ret i1 [[AND]]
+;
+  %cmp1 = icmp ult i8 %a, %b
+  %cmp2 = icmp ult i8 %b, %a
+  %and = and i1 %cmp1, %cmp2
+  ret i1 %and
+}
+
diff --git a/llvm/test/Transforms/InstSimplify/or-icmps-same-ops.ll b/llvm/test/Transforms/InstSimplify/or-icmps-same-ops.ll
index cee7fc3..326b1e1 100644
--- a/llvm/test/Transforms/InstSimplify/or-icmps-same-ops.ll
+++ b/llvm/test/Transforms/InstSimplify/or-icmps-same-ops.ll
@@ -1211,3 +1211,29 @@ define <2 x i1> @ult_ule_vec(<2 x i8> %a, <2 x i8> %b) {
   ret <2 x i1> %or
 }
 
+define i1 @ult_ne_swap(i8 %a, i8 %b) {
+; CHECK-LABEL: @ult_ne_swap(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i8 %a, %b
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp ne i8 %b, %a
+; CHECK-NEXT:    [[OR:%.*]] = or i1 [[CMP1]], [[CMP2]]
+; CHECK-NEXT:    ret i1 [[OR]]
+;
+  %cmp1 = icmp ult i8 %a, %b
+  %cmp2 = icmp ne i8 %b, %a
+  %or = or i1 %cmp1, %cmp2
+  ret i1 %or
+}
+
+define i1 @ult_ule_swap(i8 %a, i8 %b) {
+; CHECK-LABEL: @ult_ule_swap(
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp ult i8 %a, %b
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp uge i8 %b, %a
+; CHECK-NEXT:    [[OR:%.*]] = or i1 [[CMP1]], [[CMP2]]
+; CHECK-NEXT:    ret i1 [[OR]]
+;
+  %cmp1 = icmp ult i8 %a, %b
+  %cmp2 = icmp uge i8 %b, %a
+  %or = or i1 %cmp1, %cmp2
+  ret i1 %or
+}
+
-- 
2.7.4