[llvm-commits] [llvm] r60290 - in /llvm/trunk: lib/Target/README.txt lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/and-not-or.ll

[Bill Wendling]

Author: void
Date: Sun Nov 30 07:08:13 2008
New Revision: 60290

URL: http://llvm.org/viewvc/llvm-project?rev=60290&view=rev
Log:
Implement (A&((~A)|B)) -> A&B transformation in the instruction combiner. This
takes care of all permutations of this pattern.

Added:
    llvm/trunk/test/Transforms/InstCombine/and-not-or.ll
Modified:
    llvm/trunk/lib/Target/README.txt
    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp

Modified: llvm/trunk/lib/Target/README.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/README.txt?rev=60290&r1=60289&r2=60290&view=diff

==============================================================================
--- llvm/trunk/lib/Target/README.txt (original)
+++ llvm/trunk/lib/Target/README.txt Sun Nov 30 07:08:13 2008
@@ -1086,16 +1086,6 @@
 
 //===---------------------------------------------------------------------===//
 
-From GCC Bug 33512:
-int f(int y, int x)
-{
- return x & ((~x) | y);
-}
-Should combine to x & y.  Currently not optimized with "clang
--emit-llvm-bc | opt -std-compile-opts".
-
-//===---------------------------------------------------------------------===//
-
 From GCC Bug 15784:
 #define abs(x) x>0?x:-x
 int f(int x, int y)

Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=60290&r1=60289&r2=60290&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Sun Nov 30 07:08:13 2008
@@ -3993,6 +3993,7 @@
         std::swap(Op0, Op1);
       }
     }
+
     if (Op1->hasOneUse() &&
         match(Op1, m_Xor(m_Value(A), m_Value(B)))) {
       if (B == Op0) {                                // B&(A^B) -> B&(B^A)
@@ -4005,6 +4006,24 @@
         return BinaryOperator::CreateAnd(A, NotB);
       }
     }
+
+    // (A&((~A)|B)) -> A&B
+    if (match(Op0, m_Or(m_Not(m_Value(A)), m_Value(B)))) {
+      if (A == Op1)
+        return BinaryOperator::CreateAnd(A, B);
+    }
+    if (match(Op0, m_Or(m_Value(A), m_Not(m_Value(B))))) {
+      if (B == Op1)
+        return BinaryOperator::CreateAnd(A, B);
+    }
+    if (match(Op1, m_Or(m_Not(m_Value(A)), m_Value(B)))) {
+      if (A == Op0)
+        return BinaryOperator::CreateAnd(A, B);
+    }
+    if (match(Op1, m_Or(m_Value(A), m_Not(m_Value(B))))) {
+      if (B == Op0)
+        return BinaryOperator::CreateAnd(A, B);
+    }
   }
   
   if (ICmpInst *RHS = dyn_cast<ICmpInst>(Op1)) {

Added: llvm/trunk/test/Transforms/InstCombine/and-not-or.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/and-not-or.ll?rev=60290&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/and-not-or.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/and-not-or.ll Sun Nov 30 07:08:13 2008
@@ -0,0 +1,36 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {and i32 %y, %x} | count 2
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {and i32 %x, %y} | count 2
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep {xor}
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep {or}
+
+define i32 @func1(i32 %x, i32 %y) nounwind {
+entry:
+	%n = xor i32 %y, -1
+	%o = or i32 %n, %x
+	%a = and i32 %o, %y
+	ret i32 %a
+}
+
+define i32 @func2(i32 %x, i32 %y) nounwind {
+entry:
+	%n = xor i32 %y, -1
+	%o = or i32 %x, %n
+	%a = and i32 %o, %y
+	ret i32 %a
+}
+
+define i32 @func3(i32 %x, i32 %y) nounwind {
+entry:
+	%n = xor i32 %y, -1
+	%o = or i32 %n, %x
+	%a = and i32 %y, %o
+	ret i32 %a
+}
+
+define i32 @func4(i32 %x, i32 %y) nounwind {
+entry:
+	%n = xor i32 %y, -1
+	%o = or i32 %x, %n
+	%a = and i32 %y, %o
+	ret i32 %a
+}