move logic to canReplaceOperandWithVariable

Author: ellishg

llvm/lib/Transforms/Utils/Local.cpp

@@ -4224,6 +4224,14 @@ bool llvm::canReplaceOperandWithVariable(const Instruction *I, unsigned OpIdx) {
   if (I->getOperand(OpIdx)->getType()->isMetadataTy())
     return false;
 
+  // swifterror pointers can only be used by a load, store, or as a swifterror
+  // argument; swifterror pointers are not allowed to be used in select or phi
+  // instructions.
+  if ((OpIdx == 1 && isa<StoreInst>(I)) || (OpIdx == 0 && isa<LoadInst>(I)) ||
+      (OpIdx < I->getNumOperands() && isa<CallBase>(I)))
+    if (I->getOperand(OpIdx)->isSwiftError())
+      return false;
+
   // Early exit.
   if (!isa<Constant, InlineAsm>(I->getOperand(OpIdx)))
     return true;

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -2208,19 +2208,6 @@ static bool canSinkInstructions(
     if (!I->isSameOperationAs(I0, Instruction::CompareUsingIntersectedAttrs))
       return false;
 
-    // swifterror pointers can only be used by a load, store, or as a swifterror
-    // argument; sinking a load, store, or call would require introducing a
-    // select for the pointer operand, which isn't allowed for swifterror
-    // pointers.
-    if (isa<StoreInst>(I) && I->getOperand(1)->isSwiftError())
-      return false;
-    if (isa<LoadInst>(I) && I->getOperand(0)->isSwiftError())
-      return false;
-    if (const auto *CB = dyn_cast<CallBase>(I))
-      for (const Use &Arg : CB->args())
-        if (Arg->isSwiftError())
-          return false;
-
     // Treat MMRAs conservatively. This pass can be quite aggressive and
     // could drop a lot of MMRAs otherwise.
     if (MMRAMetadata(*I) != I0MMRA)

llvm/test/Transforms/SimplifyCFG/hoist-sink-swifterror-store.ll

@@ -3,7 +3,8 @@
 
 declare void @clobber1()
 declare void @clobber2()
-declare swiftcc void @swift_willThrow(ptr swifterror)
+declare swiftcc void @foo(ptr swifterror)
+declare swiftcc void @bar(ptr swifterror, ptr)
 
 ; Do not try to sink the stores to the exit block, as this requires introducing
 ; a select for the pointer operand. This is not allowed for swifterror pointers.
@@ -154,11 +155,11 @@ define swiftcc void @sink_call(i1 %c) {
 ; CHECK-NEXT:    br i1 [[C]], label [[THEN:%.*]], label [[ELSE:%.*]]
 ; CHECK:       then:
 ; CHECK-NEXT:    call void @clobber1()
-; CHECK-NEXT:    call swiftcc void @swift_willThrow(ptr [[TMP2]])
+; CHECK-NEXT:    call swiftcc void @foo(ptr [[TMP2]])
 ; CHECK-NEXT:    br label [[EXIT:%.*]]
 ; CHECK:       else:
 ; CHECK-NEXT:    call void @clobber2()
-; CHECK-NEXT:    call swiftcc void @swift_willThrow(ptr [[TMP1]])
+; CHECK-NEXT:    call swiftcc void @foo(ptr [[TMP1]])
 ; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
 ; CHECK-NEXT:    ret void
@@ -169,12 +170,50 @@ define swiftcc void @sink_call(i1 %c) {
 
 then:
   call void @clobber1()
-  call swiftcc void @swift_willThrow(ptr %3)
+  call swiftcc void @foo(ptr %3)
   br label %exit
 
 else:
   call void @clobber2()
-  call swiftcc void @swift_willThrow(ptr %2)
+  call swiftcc void @foo(ptr %2)
+  br label %exit
+
+exit:
+  ret void
+}
+
+
+define swiftcc void @safe_sink_call(i1 %c) {
+; CHECK-LABEL: define swiftcc void @safe_sink_call
+; CHECK-SAME: (i1 [[C:%.*]]) {
+; CHECK-NEXT:    [[ERR:%.*]] = alloca swifterror ptr, align 8
+; CHECK-NEXT:    [[A:%.*]] = alloca ptr, align 8
+; CHECK-NEXT:    [[B:%.*]] = alloca ptr, align 8
+; CHECK-NEXT:    br i1 [[C]], label [[THEN:%.*]], label [[ELSE:%.*]]
+; CHECK:       then:
+; CHECK-NEXT:    call void @clobber1()
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       else:
+; CHECK-NEXT:    call void @clobber2()
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[B_SINK:%.*]] = phi ptr [ [[B]], [[ELSE]] ], [ [[A]], [[THEN]] ]
+; CHECK-NEXT:    call swiftcc void @bar(ptr [[ERR]], ptr [[B_SINK]])
+; CHECK-NEXT:    ret void
+;
+  %err = alloca swifterror ptr, align 8
+  %a = alloca ptr, align 8
+  %b = alloca ptr, align 8
+  br i1 %c, label %then, label %else
+
+then:
+  call void @clobber1()
+  call swiftcc void @bar(ptr %err, ptr %a)
+  br label %exit
+
+else:
+  call void @clobber2()
+  call swiftcc void @bar(ptr %err, ptr %b)
   br label %exit
 
 exit: