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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51134 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 30 insertions, 4 deletions

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 06620557da..bb4b7016dc 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -8940,7 +8940,7 @@ bool InstCombiner::transformConstExprCastCall(CallSite CS) {
 
   // 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 @@ bool InstCombiner::runOnFunction(Function &F) {
 
   // Iterate while there is work to do.
   unsigned Iteration = 0;
-  while (DoOneIteration(F, Iteration++)) 
+  while (DoOneIteration(F, Iteration++))
     EverMadeChange = true;
   return EverMadeChange;
 }
diff --git a/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll b/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll
index 23fe07d2b3..b6930b5a65 100644
--- a/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll
+++ b/test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll
@@ -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
 }
-
diff --git a/test/Transforms/InstCombine/fp-ret-bitcast.ll b/test/Transforms/InstCombine/fp-ret-bitcast.ll
new file mode 100644
index 0000000000..00c1ea0b96
--- /dev/null
+++ b/test/Transforms/InstCombine/fp-ret-bitcast.ll
@@ -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*, ...)