[llvm-commits] [llvm] r168196 - in /llvm/trunk/lib: Analysis/InstructionSimplify.cpp Transforms/InstCombine/InstCombineCompares.cpp

[Duncan Sands]

Author: baldrick
Date: Fri Nov 16 14:53:08 2012
New Revision: 168196

URL: http://llvm.org/viewvc/llvm-project?rev=168196&view=rev
Log:
Make this easier to understand, as suggested by Chandler.

Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=168196&r1=168195&r2=168196&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Fri Nov 16 14:53:08 2012
@@ -2067,15 +2067,20 @@
       // Determine Y and Z in the form icmp (X+Y), (X+Z).
       Value *Y, *Z;
       if (A == C) {
+        // C + B == C + D  ->  B == D
         Y = B;
         Z = D;
       } else if (A == D) {
+        // D + B == C + D  ->  B == C
         Y = B;
         Z = C;
       } else if (B == C) {
+        // A + C == C + D  ->  A == D
         Y = A;
         Z = D;
-      } else if (B == D) {
+      } else {
+        assert(B == D);
+        // A + D == C + D  ->  A == C
         Y = A;
         Z = C;
       }

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=168196&r1=168195&r2=168196&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Fri Nov 16 14:53:08 2012
@@ -2358,15 +2358,20 @@
       // Determine Y and Z in the form icmp (X+Y), (X+Z).
       Value *Y, *Z;
       if (A == C) {
+        // C + B == C + D  ->  B == D
         Y = B;
         Z = D;
       } else if (A == D) {
+        // D + B == C + D  ->  B == C
         Y = B;
         Z = C;
       } else if (B == C) {
+        // A + C == C + D  ->  A == D
         Y = A;
         Z = D;
-      } else if (B == D) {
+      } else {
+        assert(B == D);
+        // A + D == C + D  ->  A == C
         Y = A;
         Z = C;
       }