Fix return attributes

Author: arsenm

llvm/test/tools/llvm-reduce/reduce-values-to-return-new-return-type.ll

@@ -51,10 +51,10 @@ bb2:
 ; INTERESTING-LABEL: define {{.+}} @callsite_different_type_unused_0(
 
 ; RESULT-LABEL: define i64 @callsite_different_type_unused_0(ptr %arg) {
-; RESULT-NEXT: %unused0 = call i64 @inst_to_return_has_different_type_but_call_result_unused(ptr %arg)
+; RESULT-NEXT: %unused0 = call range(i64 99, 1024) i64 @inst_to_return_has_different_type_but_call_result_unused(ptr %arg)
 ; RESULT-NEXT: ret i64 %unused0
 define void @callsite_different_type_unused_0(ptr %arg) {
-  %unused0 = call i64 @inst_to_return_has_different_type_but_call_result_unused(ptr %arg)
+  %unused0 = call range(i64 99, 1024) i64 @inst_to_return_has_different_type_but_call_result_unused(ptr %arg)
   %unused1 = call i64 @inst_to_return_has_different_type_but_call_result_unused(ptr null)
   ret void
 }
@@ -122,3 +122,34 @@ define void @call_multiple_returns_wrong_return_type(ptr %arg, i1 %cond, i32 %ar
   %unused = call <2 x i32> @multiple_returns_wrong_return_type(ptr %arg, i1 %cond, i32 %arg2)
   ret void
 }
+
+; INTERESTING-LABEL: @drop_incompatible_type_return_attrs(
+
+; RESULT-LABEL: define i32 @drop_incompatible_type_return_attrs(ptr %arg, float %arg1) {
+; RESULT-NEXT: %load = load i32, ptr %arg, align 4
+; RESULT-NEXT: ret i32 %load
+define nofpclass(nan inf) float @drop_incompatible_type_return_attrs(ptr %arg, float %arg1) {
+  %load = load i32, ptr %arg
+  store i32 %load, ptr @gv
+  ret float %arg1
+}
+
+; INTERESTING-LABEL: @drop_incompatible_return_range(
+; RESULT-LABEL: define i32 @drop_incompatible_return_range(ptr %arg, i64 %arg1) {
+; RESULT-NEXT: %load = load i32, ptr %arg, align 4
+; RESULT-NEXT: ret i32 %load
+define range(i64 8, 256) i64 @drop_incompatible_return_range(ptr %arg, i64 %arg1) {
+  %load = load i32, ptr %arg
+  store i32 %load, ptr @gv
+  ret i64 %arg1
+}
+
+; INTERESTING-LABEL: @preserve_compatible_return_range(
+; RESULT-LABEL: define range(i32 8, 256) i32 @preserve_compatible_return_range(ptr %arg, <2 x i32> %arg1) {
+; RESULT-NEXT: %load = load i32, ptr %arg, align 4
+; RESULT-NEXT: ret i32 %load
+define range(i32 8, 256) <2 x i32> @preserve_compatible_return_range(ptr %arg, <2 x i32> %arg1) {
+  %load = load i32, ptr %arg
+  store i32 %load, ptr @gv
+  ret <2 x i32> %arg1
+}

llvm/tools/llvm-reduce/deltas/ReduceValuesToReturn.cpp

@@ -18,6 +18,8 @@
 
 #include "Delta.h"
 #include "Utils.h"
+#include "llvm/IR/AttributeMask.h"
+#include "llvm/IR/Attributes.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
@@ -55,8 +57,10 @@ static void rewriteFuncWithReturnType(Function &OldF, Value *NewRetValue) {
   BasicBlock::iterator NewValIt =
       NewRetI ? NewRetI->getIterator() : EntryBB.end();
 
+  Type *OldRetTy = OldFuncTy->getReturnType();
+
   // Hack up any return values in other blocks, we can't leave them as ret void.
-  if (OldFuncTy->getReturnType() != NewRetTy) {
+  if (OldRetTy != NewRetTy) {
     for (BasicBlock &OtherRetBB : OldF) {
       if (&OtherRetBB != NewRetBlock) {
         auto *OrigRI = dyn_cast<ReturnInst>(OtherRetBB.getTerminator());
@@ -92,6 +96,15 @@ static void rewriteFuncWithReturnType(Function &OldF, Value *NewRetValue) {
   // result of our pruning here.
   EliminateUnreachableBlocks(OldF);
 
+
+  // Drop the incompatible attributes before we copy over to the new function.
+  if (OldRetTy != NewRetTy) {
+    AttributeList AL = OldF.getAttributes();
+    AttributeMask IncompatibleAttrs =
+        AttributeFuncs::typeIncompatible(NewRetTy, AL.getRetAttrs());
+    OldF.removeRetAttrs(IncompatibleAttrs);
+  }
+
   Function *NewF =
       Function::Create(NewFuncTy, OldF.getLinkage(), OldF.getAddressSpace(), "",
                        OldF.getParent());