[llvm-commits] [llvm] r52608 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll

[Eli Friedman]

Author: efriedma
Date: Sat Jun 21 18:36:13 2008
New Revision: 52608

URL: http://llvm.org/viewvc/llvm-project?rev=52608&view=rev
Log:
Fix for PR2479: correctly optimize expressions like (a > 13) & (a == 
15).

See also PR1800, which is about the signed case.


Added:
    llvm/trunk/test/Transforms/InstCombine/2008-06-21-CompareMiscomp.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=52608&r1=52607&r2=52608&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Sat Jun 21 18:36:13 2008
@@ -3691,8 +3691,7 @@
           case ICmpInst::ICMP_UGT:
             switch (RHSCC) {
             default: assert(0 && "Unknown integer condition code!");
-            case ICmpInst::ICMP_EQ:         // (X u> 13 & X == 15) -> X > 13
-              return ReplaceInstUsesWith(I, LHS);
+            case ICmpInst::ICMP_EQ:         // (X u> 13 & X == 15) -> X == 15
             case ICmpInst::ICMP_UGT:        // (X u> 13 & X u> 15) -> X u> 15
               return ReplaceInstUsesWith(I, RHS);
             case ICmpInst::ICMP_SGT:        // (X u> 13 & X s> 15) -> no change

Added: llvm/trunk/test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll?rev=52608&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/2008-06-21-CompareMiscomp.ll Sat Jun 21 18:36:13 2008
@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {icmp eq i32 %In, 15}
+; PR2479
+; (See also PR1800.)
+
+define i1 @test(i32 %In) {
+	%c1 = icmp ugt i32 %In, 13
+	%c2 = icmp eq i32 %In, 15
+	%V = and i1 %c1, %c2
+	ret i1 %V
+}
+