[llvm] d7fecf2 - [InstCombine] allow some commutative matches for logical-and to select fold

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2022-10-21T11:28:38-04:00
New Revision: d7fecf26f42b47f5c2e7e64a2975ec0dcccd7248

URL: https://github.com/llvm/llvm-project/commit/d7fecf26f42b47f5c2e7e64a2975ec0dcccd7248
DIFF: https://github.com/llvm/llvm-project/commit/d7fecf26f42b47f5c2e7e64a2975ec0dcccd7248.diff

LOG: [InstCombine] allow some commutative matches for logical-and to select fold

This is obviously correct for real logic instructions,
and it also works for the poison-safe variants that use
selects:
https://alive2.llvm.org/ce/z/wyHiwX

This is motivated by the lack of 'xor' folding seen in issue #58313.
This more general fold should help reduce some of those patterns,
but I'm not sure if this specific case does anything for that
particular example.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
    llvm/test/Transforms/InstCombine/select-safe-transforms.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 0f564830149e..6bed09df218a 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -2852,12 +2852,12 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
 
       // (C && A) || (!C && B) --> sel C, A, B
       if (match(FalseVal, m_LogicalAnd(m_Not(m_Value(C)), m_Value(B))) &&
-          match(CondVal, m_LogicalAnd(m_Specific(C), m_Value(A))))
+          match(CondVal, m_c_LogicalAnd(m_Specific(C), m_Value(A))))
         return SelectInst::Create(C, A, B);
 
       // (!C && A) || (C && B) --> sel C, B, A
       if (match(CondVal, m_LogicalAnd(m_Not(m_Value(C)), m_Value(A))) &&
-          match(FalseVal, m_LogicalAnd(m_Specific(C), m_Value(B))))
+          match(FalseVal, m_c_LogicalAnd(m_Specific(C), m_Value(B))))
         return SelectInst::Create(C, B, A);
     }
   }

diff  --git a/llvm/test/Transforms/InstCombine/select-safe-transforms.ll b/llvm/test/Transforms/InstCombine/select-safe-transforms.ll
index 59298e0f5245..852675823836 100644
--- a/llvm/test/Transforms/InstCombine/select-safe-transforms.ll
+++ b/llvm/test/Transforms/InstCombine/select-safe-transforms.ll
@@ -271,10 +271,7 @@ define i1 @bools_logical_commute1_and1_and2(i1 %b, i1 %c) {
 
 define <2 x i1> @bools_logical_commute2(<2 x i1> %a, <2 x i1> %b, <2 x i1> %c) {
 ; CHECK-LABEL: @bools_logical_commute2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor <2 x i1> [[C:%.*]], <i1 true, i1 true>
-; CHECK-NEXT:    [[AND1:%.*]] = select <2 x i1> [[NOT]], <2 x i1> [[A:%.*]], <2 x i1> zeroinitializer
-; CHECK-NEXT:    [[AND2:%.*]] = select <2 x i1> [[B:%.*]], <2 x i1> [[C]], <2 x i1> zeroinitializer
-; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[AND1]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[C:%.*]], <2 x i1> [[B:%.*]], <2 x i1> [[A:%.*]]
 ; CHECK-NEXT:    ret <2 x i1> [[OR]]
 ;
   %not = xor <2 x i1> %c, <i1 -1, i1 -1>
@@ -286,10 +283,7 @@ define <2 x i1> @bools_logical_commute2(<2 x i1> %a, <2 x i1> %b, <2 x i1> %c) {
 
 define <2 x i1> @bools_logical_commute2_and1(<2 x i1> %a, <2 x i1> %b, <2 x i1> %c) {
 ; CHECK-LABEL: @bools_logical_commute2_and1(
-; CHECK-NEXT:    [[NOT:%.*]] = xor <2 x i1> [[C:%.*]], <i1 true, i1 true>
-; CHECK-NEXT:    [[AND1:%.*]] = and <2 x i1> [[NOT]], [[A:%.*]]
-; CHECK-NEXT:    [[AND2:%.*]] = select <2 x i1> [[B:%.*]], <2 x i1> [[C]], <2 x i1> zeroinitializer
-; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[AND1]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[C:%.*]], <2 x i1> [[B:%.*]], <2 x i1> [[A:%.*]]
 ; CHECK-NEXT:    ret <2 x i1> [[OR]]
 ;
   %not = xor <2 x i1> %c, <i1 -1, i1 -1>
@@ -301,10 +295,7 @@ define <2 x i1> @bools_logical_commute2_and1(<2 x i1> %a, <2 x i1> %b, <2 x i1>
 
 define <2 x i1> @bools_logical_commute2_and2(<2 x i1> %a, <2 x i1> %b, <2 x i1> %c) {
 ; CHECK-LABEL: @bools_logical_commute2_and2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor <2 x i1> [[C:%.*]], <i1 true, i1 true>
-; CHECK-NEXT:    [[AND1:%.*]] = select <2 x i1> [[NOT]], <2 x i1> [[A:%.*]], <2 x i1> zeroinitializer
-; CHECK-NEXT:    [[AND2:%.*]] = and <2 x i1> [[B:%.*]], [[C]]
-; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[AND1]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[C:%.*]], <2 x i1> [[B:%.*]], <2 x i1> [[A:%.*]]
 ; CHECK-NEXT:    ret <2 x i1> [[OR]]
 ;
   %not = xor <2 x i1> %c, <i1 -1, i1 -1>
@@ -316,10 +307,7 @@ define <2 x i1> @bools_logical_commute2_and2(<2 x i1> %a, <2 x i1> %b, <2 x i1>
 
 define <2 x i1> @bools_logical_commute2_and1_and2(<2 x i1> %a, <2 x i1> %b, <2 x i1> %c) {
 ; CHECK-LABEL: @bools_logical_commute2_and1_and2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor <2 x i1> [[C:%.*]], <i1 true, i1 true>
-; CHECK-NEXT:    [[AND1:%.*]] = and <2 x i1> [[NOT]], [[A:%.*]]
-; CHECK-NEXT:    [[AND2:%.*]] = and <2 x i1> [[B:%.*]], [[C]]
-; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[AND1]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select <2 x i1> [[C:%.*]], <2 x i1> [[B:%.*]], <2 x i1> [[A:%.*]]
 ; CHECK-NEXT:    ret <2 x i1> [[OR]]
 ;
   %not = xor <2 x i1> %c, <i1 -1, i1 -1>
@@ -443,10 +431,7 @@ define i1 @bools2_logical_commute0_and1_and2(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools2_logical_commute1(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools2_logical_commute1(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = select i1 [[A:%.*]], i1 [[C]], i1 false
-; CHECK-NEXT:    [[AND2:%.*]] = select i1 [[NOT]], i1 [[B:%.*]], i1 false
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[AND1]], i1 true, i1 [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select i1 [[C:%.*]], i1 [[A:%.*]], i1 [[B:%.*]]
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %not = xor i1 %c, -1
@@ -458,10 +443,7 @@ define i1 @bools2_logical_commute1(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools2_logical_commute1_and1(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools2_logical_commute1_and1(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = and i1 [[A:%.*]], [[C]]
-; CHECK-NEXT:    [[AND2:%.*]] = select i1 [[NOT]], i1 [[B:%.*]], i1 false
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[AND1]], i1 true, i1 [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select i1 [[C:%.*]], i1 [[A:%.*]], i1 [[B:%.*]]
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %not = xor i1 %c, -1
@@ -473,10 +455,7 @@ define i1 @bools2_logical_commute1_and1(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools2_logical_commute1_and2(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools2_logical_commute1_and2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = select i1 [[A:%.*]], i1 [[C]], i1 false
-; CHECK-NEXT:    [[AND2:%.*]] = and i1 [[NOT]], [[B:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[AND1]], i1 true, i1 [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select i1 [[C:%.*]], i1 [[A:%.*]], i1 [[B:%.*]]
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %not = xor i1 %c, -1
@@ -488,10 +467,7 @@ define i1 @bools2_logical_commute1_and2(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools2_logical_commute1_and1_and2(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools2_logical_commute1_and1_and2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = and i1 [[A:%.*]], [[C]]
-; CHECK-NEXT:    [[AND2:%.*]] = and i1 [[NOT]], [[B:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[AND1]], i1 true, i1 [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select i1 [[C:%.*]], i1 [[A:%.*]], i1 [[B:%.*]]
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %not = xor i1 %c, -1