[PATCH] D93841: [GVN] Use m_LogicalAnd/Or to propagate equality from branch conditions

[Juneyoung Lee via Phabricator via llvm-commits]

aqjune created this revision.
aqjune added reviewers: nikic, lebedev.ri, spatel.
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This patch makes GVN recognize `select c1, c2, false` as well as `select c1, true, c2`
branch condition and propagate equality from these.

See llvm.org/pr48353, D93065 <https://reviews.llvm.org/D93065>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D93841

Files:
  llvm/lib/Transforms/Scalar/GVN.cpp
  llvm/test/Transforms/GVN/condprop.ll


Index: llvm/test/Transforms/GVN/condprop.ll
===================================================================
--- llvm/test/Transforms/GVN/condprop.ll
+++ llvm/test/Transforms/GVN/condprop.ll
@@ -87,13 +87,13 @@
   br i1 %z, label %both_zero, label %nope
 both_zero:
   call void @foo(i1 %xz)
-; CHECK: call void @foo(i1 %xz)
+; CHECK: call void @foo(i1 true)
   call void @foo(i1 %yz)
-; CHECK: call void @foo(i1 %yz)
+; CHECK: call void @foo(i1 true)
   call void @bar(i32 %x)
-; CHECK: call void @bar(i32 %x)
+; CHECK: call void @bar(i32 0)
   call void @bar(i32 %y)
-; CHECK: call void @bar(i32 %y)
+; CHECK: call void @bar(i32 0)
   ret void
 nope:
   call void @foo(i1 %z)
@@ -131,13 +131,13 @@
   br i1 %z, label %nope, label %both_zero
 both_zero:
   call void @foo(i1 %xz)
-; CHECK: call void @foo(i1 %xz)
+; CHECK: call void @foo(i1 false)
   call void @foo(i1 %yz)
-; CHECK: call void @foo(i1 %yz)
+; CHECK: call void @foo(i1 false)
   call void @bar(i32 %x)
-; CHECK: call void @bar(i32 %x)
+; CHECK: call void @bar(i32 0)
   call void @bar(i32 %y)
-; CHECK: call void @bar(i32 %y)
+; CHECK: call void @bar(i32 0)
   ret void
 nope:
   call void @foo(i1 %z)
Index: llvm/lib/Transforms/Scalar/GVN.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/GVN.cpp
+++ llvm/lib/Transforms/Scalar/GVN.cpp
@@ -2087,8 +2087,8 @@
     // If "A && B" is known true then both A and B are known true.  If "A || B"
     // is known false then both A and B are known false.
     Value *A, *B;
-    if ((isKnownTrue && match(LHS, m_And(m_Value(A), m_Value(B)))) ||
-        (isKnownFalse && match(LHS, m_Or(m_Value(A), m_Value(B))))) {
+    if ((isKnownTrue && match(LHS, m_LogicalAnd(m_Value(A), m_Value(B)))) ||
+        (isKnownFalse && match(LHS, m_LogicalOr(m_Value(A), m_Value(B))))) {
       Worklist.push_back(std::make_pair(A, RHS));
       Worklist.push_back(std::make_pair(B, RHS));
       continue;


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