[llvm-commits] [llvm] r127574 - /llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp

[Jin-Gu Kang]

Author: jaykang10
Date: Sun Mar 13 20:21:00 2011
New Revision: 127574

URL: http://llvm.org/viewvc/llvm-project?rev=127574&view=rev
Log:
This case is solved by Scalar Replacement of Aggregates (DT) and
Early CSE pass so this patch reverts it to original source code.

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=127574&r1=127573&r2=127574&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp Sun Mar 13 20:21:00 2011
@@ -429,31 +429,9 @@
     // 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 (equivalentAddressValues(LI->getOperand(0), Ptr) &&
-          !SI.isVolatile()) {
-        if (LI == Val)
-          return EraseInstFromFunction(SI);
-        // load and store reference same memory location, the memory location
-        // is represented by getelementptr with two uses (load and store) and
-        // the getelementptr's base is alloca with single use. At this point,
-        // instructions from alloca to store can be removed.
-        // (this pattern is generated when bitfield is accessed.)
-        // For example,
-        // %u = alloca %struct.test, align 4               ; [#uses=1]
-        // %0 = getelementptr inbounds %struct.test* %u, i32 0, i32 0;[#uses=2]
-        // %1 = load i8* %0, align 4                       ; [#uses=1]
-        // %2 = and i8 %1, -16                             ; [#uses=1]
-        // %3 = or i8 %2, 5                                ; [#uses=1]
-        // store i8 %3, i8* %0, align 4
-        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);
-            }
-          }
-        }
-      }
+      if (LI == Val && equivalentAddressValues(LI->getOperand(0), Ptr) &&
+          !SI.isVolatile())
+        return EraseInstFromFunction(SI);
       
       // Otherwise, this is a load from some other location.  Stores before it
       // may not be dead.