[llvm] bf75e93 - [InstCombine] match logical and/or more generally in fold to select

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2022-10-21T09:03:36-04:00
New Revision: bf75e937bbc3d59225474e4a3ca3517723ac75dc

URL: https://github.com/llvm/llvm-project/commit/bf75e937bbc3d59225474e4a3ca3517723ac75dc
DIFF: https://github.com/llvm/llvm-project/commit/bf75e937bbc3d59225474e4a3ca3517723ac75dc.diff

LOG: [InstCombine] match logical and/or more generally in fold to select

This allows the regular bitwise logic opcodes in addition to the
poison-safe select variants:
https://alive2.llvm.org/ce/z/8xB9gy

Handling commuted variants safely is likely trickier, so that's
left to another patch.

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 6ade18f898a7c..756bece653f91 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -2847,12 +2847,12 @@ Instruction *InstCombinerImpl::visitSelectInst(SelectInst &SI) {
         return replaceOperand(SI, 0, A);
     }
 
-    // sel (sel c, a, false), true, (sel !c, b, false) -> sel c, a, b
-    // sel (sel !c, a, false), true, (sel c, b, false) -> sel c, b, a
+    // (c && a)  || (!c && b) --> sel c, a, b
+    // (!c && a) ||  (c && b) --> sel c, b, a
     Value *C1, *C2;
-    if (match(CondVal, m_Select(m_Value(C1), m_Value(A), m_Zero())) &&
+    if (match(CondVal, m_LogicalAnd(m_Value(C1), m_Value(A))) &&
         match(TrueVal, m_One()) &&
-        match(FalseVal, m_Select(m_Value(C2), m_Value(B), m_Zero()))) {
+        match(FalseVal, m_LogicalAnd(m_Value(C2), m_Value(B)))) {
       if (match(C2, m_Not(m_Specific(C1)))) // first case
         return SelectInst::Create(C1, A, B);
       else if (match(C1, m_Not(m_Specific(C2)))) // second case

diff  --git a/llvm/test/Transforms/InstCombine/select-safe-transforms.ll b/llvm/test/Transforms/InstCombine/select-safe-transforms.ll
index f02eb670a5490..59298e0f52459 100644
--- a/llvm/test/Transforms/InstCombine/select-safe-transforms.ll
+++ b/llvm/test/Transforms/InstCombine/select-safe-transforms.ll
@@ -171,10 +171,7 @@ define i1 @bools_logical_commute0(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools_logical_commute0_and1(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools_logical_commute0_and1(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = and i1 [[NOT]], [[A:%.*]]
-; CHECK-NEXT:    [[AND2:%.*]] = select i1 [[C]], i1 [[B:%.*]], i1 false
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[AND1]], i1 true, i1 [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select i1 [[C:%.*]], i1 [[B:%.*]], i1 [[A:%.*]]
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %not = xor i1 %c, -1
@@ -186,10 +183,7 @@ define i1 @bools_logical_commute0_and1(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools_logical_commute0_and2(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools_logical_commute0_and2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = select i1 [[NOT]], i1 [[A:%.*]], i1 false
-; CHECK-NEXT:    [[AND2:%.*]] = and i1 [[C]], [[B:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[AND1]], i1 true, i1 [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select i1 [[C:%.*]], i1 [[B:%.*]], i1 [[A:%.*]]
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %not = xor i1 %c, -1
@@ -201,10 +195,7 @@ define i1 @bools_logical_commute0_and2(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools_logical_commute0_and1_and2(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools_logical_commute0_and1_and2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = and i1 [[NOT]], [[A:%.*]]
-; CHECK-NEXT:    [[AND2:%.*]] = and i1 [[C]], [[B:%.*]]
-; CHECK-NEXT:    [[OR:%.*]] = select i1 [[AND1]], i1 true, i1 [[AND2]]
+; CHECK-NEXT:    [[OR:%.*]] = select i1 [[C:%.*]], i1 [[B:%.*]], i1 [[A:%.*]]
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %not = xor i1 %c, -1
@@ -416,10 +407,7 @@ define i1 @bools2_logical_commute0(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools2_logical_commute0_and1(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools2_logical_commute0_and1(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = and i1 [[C]], [[A:%.*]]
-; 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
@@ -431,10 +419,7 @@ define i1 @bools2_logical_commute0_and1(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools2_logical_commute0_and2(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools2_logical_commute0_and2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = select i1 [[C]], i1 [[A:%.*]], 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
@@ -446,10 +431,7 @@ define i1 @bools2_logical_commute0_and2(i1 %a, i1 %b, i1 %c) {
 
 define i1 @bools2_logical_commute0_and1_and2(i1 %a, i1 %b, i1 %c) {
 ; CHECK-LABEL: @bools2_logical_commute0_and1_and2(
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[C:%.*]], true
-; CHECK-NEXT:    [[AND1:%.*]] = and i1 [[C]], [[A:%.*]]
-; 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