[cfe-commits] r64295 - in /cfe/trunk: lib/CodeGen/CGExprScalar.cpp test/CodeGen/exprs.c

[Chris Lattner]

Author: lattner
Date: Wed Feb 11 01:21:43 2009
New Revision: 64295

URL: http://llvm.org/viewvc/llvm-project?rev=64295&view=rev
Log:
finish off codegen support for sub of pointer to functions, 
finishing off rdar://6520707

Modified:
    cfe/trunk/lib/CodeGen/CGExprScalar.cpp
    cfe/trunk/test/CodeGen/exprs.c

Modified: cfe/trunk/lib/CodeGen/CGExprScalar.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprScalar.cpp?rev=64295&r1=64294&r2=64295&view=diff

==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprScalar.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp Wed Feb 11 01:21:43 2009
@@ -965,8 +965,9 @@
   
     uint64_t ElementSize;
 
-    // Handle GCC extension for pointer arithmetic on void* types.
-    if (LHSElementType->isVoidType()) {
+    // Handle GCC extension for pointer arithmetic on void* and function pointer
+    // types.
+    if (LHSElementType->isVoidType() || LHSElementType->isFunctionType()) {
       ElementSize = 1;
     } else {
       ElementSize = CGF.getContext().getTypeSize(LHSElementType) / 8;
@@ -977,6 +978,10 @@
     RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
     Value *BytesBetween = Builder.CreateSub(LHS, RHS, "sub.ptr.sub");
     
+    // Optimize out the shift for element size of 1.
+    if (ElementSize == 1)
+      return BytesBetween;
+    
     // HACK: LLVM doesn't have an divide instruction that 'knows' there is no
     // remainder.  As such, we handle common power-of-two cases here to generate
     // better code. See PR2247.

Modified: cfe/trunk/test/CodeGen/exprs.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/exprs.c?rev=64295&r1=64294&r2=64295&view=diff

==============================================================================
--- cfe/trunk/test/CodeGen/exprs.c (original)
+++ cfe/trunk/test/CodeGen/exprs.c Wed Feb 11 01:21:43 2009
@@ -52,3 +52,10 @@
 	if (*t)
 		return;
 }
+
+// rdar://6520707
+void f0(void (*fp)(void), void (*fp2)(void)) {
+  int x = fp - fp2;
+}
+
+