[llvm-commits] [llvm] r51134 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll test/Transforms/InstCombine/fp-ret-bitcast.ll

[Bill Wendling]

Author: void
Date: Wed May 14 17:45:20 2008
New Revision: 51134

URL: http://llvm.org/viewvc/llvm-project?rev=51134&view=rev
Log:
Situations can arise when you have a function called that returns a 'void', but
is bitcast to return a floating point value. The result of the instruction may
not be used by the program afterwards, and LLVM will happily remove all
instructions except the call. But, on some platforms, if a value is returned as
a floating point, it may need to be removed from the stack (like x87). Thus, we
can't get rid of the bitcast even if there isn't a use of the value.

Added:
    llvm/trunk/test/Transforms/InstCombine/fp-ret-bitcast.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
    llvm/trunk/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll

Modified: llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp?rev=51134&r1=51133&r2=51134&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/InstructionCombining.cpp Wed May 14 17:45:20 2008
@@ -8940,7 +8940,7 @@
 
   // Check to see if we are changing the return type...
   if (OldRetTy != FT->getReturnType()) {
-    if (Callee->isDeclaration() && !Caller->use_empty() && 
+    if (Callee->isDeclaration() &&
         // Conversion is ok if changing from pointer to int of same size.
         !(isa<PointerType>(FT->getReturnType()) &&
           TD->getIntPtrType() == OldRetTy))
@@ -11516,7 +11516,7 @@
 
   // Iterate while there is work to do.
   unsigned Iteration = 0;
-  while (DoOneIteration(F, Iteration++)) 
+  while (DoOneIteration(F, Iteration++))
     EverMadeChange = true;
   return EverMadeChange;
 }

Modified: llvm/trunk/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll?rev=51134&r1=51133&r2=51134&view=diff

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll Wed May 14 17:45:20 2008
@@ -3,7 +3,6 @@
 declare void @free(i8*)
 
 define void @test(i32* %X) {
-        call i32 (...)* bitcast (void (i8*)* @free to i32 (...)*)( i32* %X )            ; <i32>:1 [#uses=0]
+        call void (...)* bitcast (void (i8*)* @free to void (...)*)( i32* %X )          ; <i32>:1 [#uses=0]
         ret void
 }
-

Added: llvm/trunk/test/Transforms/InstCombine/fp-ret-bitcast.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fp-ret-bitcast.ll?rev=51134&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fp-ret-bitcast.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/fp-ret-bitcast.ll Wed May 14 17:45:20 2008
@@ -0,0 +1,27 @@
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | \
+; RUN:    grep {call float bitcast} | count 1
+	%struct.NSObject = type { %struct.objc_class* }
+ 	%struct.NSArray = type { %struct.NSObject }
+	%struct.objc_class = type opaque
+ 	%struct.objc_selector = type opaque
+
+@"\01L_OBJC_METH_VAR_NAME_112" = internal global [15 x i8] c"whiteComponent\00", section "__TEXT,__cstring,cstring_literals"
+@"\01L_OBJC_SELECTOR_REFERENCES_81" = internal global %struct.objc_selector* bitcast ([15 x i8]* @"\01L_OBJC_METH_VAR_NAME_112" to %struct.objc_selector*), section "__OBJC,__message_refs,literal_pointers,no_dead_strip"
+
+define void @bork() nounwind  {
+entry:
+	%color = alloca %struct.NSArray*
+	%color.466 = alloca %struct.NSObject*
+	%tmp103 = load %struct.NSArray** %color, align 4
+	%tmp103104 = getelementptr %struct.NSArray* %tmp103, i32 0, i32 0
+	store %struct.NSObject* %tmp103104, %struct.NSObject** %color.466, align 4
+	%tmp105 = load %struct.objc_selector** @"\01L_OBJC_SELECTOR_REFERENCES_81", align 4
+	%tmp106 = load %struct.NSObject** %color.466, align 4
+	%tmp107 = call float bitcast (void (%struct.NSObject*, ...)* @objc_msgSend_fpret to float (%struct.NSObject*, %struct.objc_selector*)*)( %struct.NSObject* %tmp106, %struct.objc_selector* %tmp105 ) nounwind
+	br label %exit
+
+exit:
+	ret void
+}
+
+declare void @objc_msgSend_fpret(%struct.NSObject*, ...)