[PATCH] D145157: [InstCombine] Implement "A & (~A | B) --> A & B" for boolean vectors.

[Paul Walker via Phabricator via llvm-commits]

paulwalker-arm updated this revision to Diff 501865.
paulwalker-arm added a comment.

Updated to include correct handling of poison.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D145157/new/

https://reviews.llvm.org/D145157

Files:
  llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
  llvm/test/Transforms/InstCombine/logical-select.ll


Index: llvm/test/Transforms/InstCombine/logical-select.ll
===================================================================
--- llvm/test/Transforms/InstCombine/logical-select.ll
+++ llvm/test/Transforms/InstCombine/logical-select.ll
@@ -1121,3 +1121,27 @@
   call void @use1(i1 %and1)
   ret i1 %r
 }
+
+; A & (~A | B) --> A & B
+define <2 x i1> @and_commute1(<2 x i1> %a, <2 x i1> %b) {
+; CHECK-LABEL: @and_commute1(
+; CHECK-NEXT:    [[AND:%.*]] = select <2 x i1> [[A:%.*]], <2 x i1> [[B:%.*]], <2 x i1> zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[AND]]
+;
+  %not = xor <2 x i1> %a, <i1 true, i1 true>
+  %or = or <2 x i1> %b, %not
+  %and = select <2 x i1> %a, <2 x i1> %or, <2 x i1> zeroinitializer
+  ret <2 x i1> %and
+}
+
+; A & (~A | B) --> A & B
+define <2 x i1> @and_commute2(<2 x i1> %a, <2 x i1> %b) {
+; CHECK-LABEL: @and_commute2(
+; CHECK-NEXT:    [[AND:%.*]] = select <2 x i1> [[A:%.*]], <2 x i1> [[B:%.*]], <2 x i1> zeroinitializer
+; CHECK-NEXT:    ret <2 x i1> [[AND]]
+;
+  %not = xor <2 x i1> %a, <i1 true, i1 true>
+  %or = select <2 x i1> %not, <2 x i1> <i1 true, i1 true>, <2 x i1> %b
+  %and = select <2 x i1> %a, <2 x i1> %or, <2 x i1> zeroinitializer
+  ret <2 x i1> %and
+}
Index: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -2984,6 +2984,10 @@
   if (match(CondVal, m_Select(m_Value(A), m_Value(B), m_Zero())) &&
       match(TrueVal, m_Specific(B)) && match(FalseVal, m_Zero()))
     return replaceOperand(SI, 0, A);
+  // select a, (select ~a, true, b), false -> select a, b, false
+  if (match(TrueVal, m_c_LogicalOr(m_Not(m_Specific(CondVal)), m_Value(B))) &&
+      match(FalseVal, m_Zero()))
+    return replaceOperand(SI, 1, B);
 
   // ~(A & B) & (A | B) --> A ^ B
   if (match(&SI, m_c_LogicalAnd(m_Not(m_LogicalAnd(m_Value(A), m_Value(B))),


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