[llvm-commits] [llvm] r146624 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineSelect.cpp test/Transforms/InstCombine/select.ll

[Pete Cooper]

Author: pete
Date: Wed Dec 14 18:56:45 2011
New Revision: 146624

URL: http://llvm.org/viewvc/llvm-project?rev=146624&view=rev
Log:
Added InstCombine for "select cond, ~cond, x" type patterns

These can be reduced to "~cond & x" or "~cond | x"

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
    llvm/trunk/test/Transforms/InstCombine/select.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp?rev=146624&r1=146623&r2=146624&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineSelect.cpp Wed Dec 14 18:56:45 2011
@@ -682,6 +682,13 @@
       return BinaryOperator::CreateOr(CondVal, FalseVal);
     else if (CondVal == FalseVal)
       return BinaryOperator::CreateAnd(CondVal, TrueVal);
+
+    // select a, ~a, b -> (~a)&b
+    // select a, b, ~a -> (~a)|b
+    if (match(TrueVal, m_Not(m_Specific(CondVal))))
+      return BinaryOperator::CreateAnd(TrueVal, FalseVal);
+    else if (match(FalseVal, m_Not(m_Specific(CondVal))))
+      return BinaryOperator::CreateOr(TrueVal, FalseVal);
   }
 
   // Selecting between two integer constants?

Modified: llvm/trunk/test/Transforms/InstCombine/select.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/select.ll?rev=146624&r1=146623&r2=146624&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/select.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/select.ll Wed Dec 14 18:56:45 2011
@@ -809,3 +809,23 @@
 ; CHECK: @test61
 ; CHECK: ret i32 10
 }
+
+define i1 @test62(i1 %A, i1 %B) {
+        %not = xor i1 %A, true
+        %C = select i1 %A, i1 %not, i1 %B             
+        ret i1 %C
+; CHECK: @test62
+; CHECK: %not = xor i1 %A, true
+; CHECK: %C = and i1 %not, %B
+; CHECK: ret i1 %C
+}
+
+define i1 @test63(i1 %A, i1 %B) {
+        %not = xor i1 %A, true
+        %C = select i1 %A, i1 %B, i1 %not         
+        ret i1 %C
+; CHECK: @test63
+; CHECK: %not = xor i1 %A, true
+; CHECK: %C = or i1 %B, %not
+; CHECK: ret i1 %C
+}