[llvm-commits] [llvm] r58351 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/logical-select.ll

[Dan Gohman]

Author: djg
Date: Tue Oct 28 17:38:57 2008
New Revision: 58351

URL: http://llvm.org/viewvc/llvm-project?rev=58351&view=rev
Log:
(A & sext(C)) | (B & ~sext(C)  ->  C ? A : B

Added:
    llvm/trunk/test/Transforms/InstCombine/logical-select.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=58351&r1=58350&r2=58351&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Tue Oct 28 17:38:57 2008
@@ -4337,6 +4337,25 @@
         return BinaryOperator::CreateAnd(V1, Or);
       }
     }
+
+    // (A & sext(C0)) | (B & ~sext(C0) ->  C0 ? A : B
+    if (isa<SExtInst>(C) &&
+        cast<User>(C)->getOperand(0)->getType() == Type::Int1Ty) {
+      if (match(D, m_Not(m_Value(C))))
+        return SelectInst::Create(cast<User>(C)->getOperand(0), A, B);
+      // And commutes, try both ways.
+      if (match(B, m_Not(m_Value(C))))
+        return SelectInst::Create(cast<User>(C)->getOperand(0), A, D);
+    }
+    // Or commutes, try both ways.
+    if (isa<SExtInst>(D) &&
+        cast<User>(D)->getOperand(0)->getType() == Type::Int1Ty) {
+      if (match(C, m_Not(m_Value(D))))
+        return SelectInst::Create(cast<User>(D)->getOperand(0), A, B);
+      // And commutes, try both ways.
+      if (match(A, m_Not(m_Value(D))))
+        return SelectInst::Create(cast<User>(D)->getOperand(0), C, B);
+    }
   }
   
   // (X >> Z) | (Y >> Z)  -> (X|Y) >> Z  for all shifts.

Added: llvm/trunk/test/Transforms/InstCombine/logical-select.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/logical-select.ll?rev=58351&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/logical-select.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/logical-select.ll Tue Oct 28 17:38:57 2008
@@ -0,0 +1,20 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep select | count 2
+
+define i32 @foo(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
+  %e = icmp slt i32 %a, %b
+  %f = sext i1 %e to i32
+  %g = and i32 %c, %f
+  %h = xor i32 %f, -1
+  %i = and i32 %d, %h
+  %j = or i32 %g, %i
+  ret i32 %j
+}
+define i32 @bar(i32 %a, i32 %b, i32 %c, i32 %d) nounwind {
+  %e = icmp slt i32 %a, %b
+  %f = sext i1 %e to i32
+  %g = and i32 %c, %f
+  %h = xor i32 %f, -1
+  %i = and i32 %d, %h
+  %j = or i32 %i, %g
+  ret i32 %j
+}