[llvm-commits] [llvm] r127539 - /llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

[Jin-Gu Kang]

Author: jaykang10
Date: Sat Mar 12 06:18:44 2011
New Revision: 127539

URL: http://llvm.org/viewvc/llvm-project?rev=127539&view=rev
Log:
This patch removes some of useless instructions generated by bitfield access.

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp?rev=127539&r1=127538&r2=127539&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp Sat Mar 12 06:18:44 2011
@@ -429,9 +429,19 @@
     // the pointer we're loading and is producing the pointer we're storing,
     // then *this* store is dead (X = load P; store X -> P).
     if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) {
-      if (LI == Val && equivalentAddressValues(LI->getOperand(0), Ptr) &&
-          !SI.isVolatile())
-        return EraseInstFromFunction(SI);
+      if (equivalentAddressValues(LI->getOperand(0), Ptr) &&
+          !SI.isVolatile()) {
+        if (LI == Val)
+          return EraseInstFromFunction(SI);
+        if (Ptr->hasNUses(2)) {
+          if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Ptr)) {
+            if (isa<AllocaInst>(GEP->getOperand(0))) {
+              if (GEP->getOperand(0)->hasOneUse())
+                return EraseInstFromFunction(SI);
+            }
+          }
+        }
+      }
       
       // Otherwise, this is a load from some other location.  Stores before it
       // may not be dead.