[cfe-commits] r162701 - in /cfe/trunk: lib/CodeGen/CGDecl.cpp test/CodeGen/init.c

[Benjamin Kramer]

Author: d0k
Date: Mon Aug 27 16:35:58 2012
New Revision: 162701

URL: http://llvm.org/viewvc/llvm-project?rev=162701&view=rev
Log:
CodeGen: When emitting stores for an initializer, only emit a GEP if we really need the store.

This avoids emitting many dead GEPs for large zero-initialized arrays.

Modified:
    cfe/trunk/lib/CodeGen/CGDecl.cpp
    cfe/trunk/test/CodeGen/init.c

Modified: cfe/trunk/lib/CodeGen/CGDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDecl.cpp?rev=162701&r1=162700&r2=162701&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGDecl.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGDecl.cpp Mon Aug 27 16:35:58 2012
@@ -719,10 +719,11 @@
         dyn_cast<llvm::ConstantDataSequential>(Init)) {
     for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
       llvm::Constant *Elt = CDS->getElementAsConstant(i);
-      
-      // Get a pointer to the element and emit it.
-      emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
-                                   isVolatile, Builder);
+
+      // If necessary, get a pointer to the element and emit it.
+      if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
+        emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
+                                     isVolatile, Builder);
     }
     return;
   }
@@ -732,9 +733,11 @@
 
   for (unsigned i = 0, e = Init->getNumOperands(); i != e; ++i) {
     llvm::Constant *Elt = cast<llvm::Constant>(Init->getOperand(i));
-    // Get a pointer to the element and emit it.
-    emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
-                                 isVolatile, Builder);
+
+    // If necessary, get a pointer to the element and emit it.
+    if (!Elt->isNullValue() && !isa<llvm::UndefValue>(Elt))
+      emitStoresForInitAfterMemset(Elt, Builder.CreateConstGEP2_32(Loc, 0, i),
+                                   isVolatile, Builder);
   }
 }
 

Modified: cfe/trunk/test/CodeGen/init.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/init.c?rev=162701&r1=162700&r2=162701&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/init.c (original)
+++ cfe/trunk/test/CodeGen/init.c Mon Aug 27 16:35:58 2012
@@ -69,6 +69,8 @@
 // CHECK: store i8 97
 // CHECK: store i8 98
 // CHECK: store i8 99
+// CHECK-NOT: getelementptr
+// CHECK: load
 }
 
 void bar(void*);