ARM: Use a callee save register for the swiftself parameter.
It is very likely that the swiftself parameter is alive throughout most
functions function so putting it into a callee save register should
avoid spills for the callers with only a minimum amount of extra spills
in the callees.
Currently the generated code is correct but unnecessarily spills and
reloads arguments passed in callee save registers, I will address this
in upcoming patches.
This also adds a missing check that for tail calls the preserved value
of the caller must be the same as the callees parameter.
Differential Revision: http://reviews.llvm.org/D18901
llvm-svn: 266253
diff --git a/llvm/test/CodeGen/ARM/swiftself.ll b/llvm/test/CodeGen/ARM/swiftself.ll
index cbeedc4..6826b12 100644
--- a/llvm/test/CodeGen/ARM/swiftself.ll
+++ b/llvm/test/CodeGen/ARM/swiftself.ll
@@ -1,32 +1,65 @@
-; RUN: llc -verify-machineinstrs < %s -mtriple=armv7k-apple-ios8.0 -mcpu=cortex-a7 | FileCheck --check-prefix=CHECK-APPLE %s
-; RUN: llc -O0 -verify-machineinstrs < %s -mtriple=armv7k-apple-ios8.0 -mcpu=cortex-a7 | FileCheck --check-prefix=CHECK-O0 %s
+; RUN: llc -verify-machineinstrs -mtriple=armv7k-apple-ios8.0 -mcpu=cortex-a7 -o - %s | FileCheck --check-prefix=CHECK --check-prefix=OPT --check-prefix=TAILCALL %s
+; RUN: llc -O0 -verify-machineinstrs -mtriple=armv7k-apple-ios8.0 -mcpu=cortex-a7 -o - %s | FileCheck %s
-; RUN: llc -verify-machineinstrs < %s -mtriple=armv7-apple-ios | FileCheck --check-prefix=CHECK-APPLE %s
-; RUN: llc -O0 -verify-machineinstrs < %s -mtriple=armv7-apple-ios | FileCheck --check-prefix=CHECK-O0 %s
+; RUN: llc -verify-machineinstrs -mtriple=armv7-apple-ios -o - %s | FileCheck --check-prefix=CHECK --check-prefix=OPT %s
+; RUN: llc -O0 -verify-machineinstrs -mtriple=armv7-apple-ios -o - %s | FileCheck %s
-; Parameter with swiftself should be allocated to r9.
-define void @check_swiftself(i32* swiftself %addr0) {
-; CHECK-APPLE-LABEL: check_swiftself:
-; CHECK-O0-LABEL: check_swiftself:
-
- %val0 = load volatile i32, i32* %addr0
-; CHECK-APPLE: ldr r{{.*}}, [r9]
-; CHECK-O0: ldr r{{.*}}, [r9]
- ret void
+; Parameter with swiftself should be allocated to r10.
+; CHECK-LABEL: swiftself_param:
+; CHECK: mov r0, r10
+define i8 *@swiftself_param(i8* swiftself %addr0) {
+ ret i8 *%addr0
}
-@var8_3 = global i8 0
-declare void @take_swiftself(i8* swiftself %addr0)
+; Check that r10 is used to pass a swiftself argument.
+; CHECK-LABEL: call_swiftself:
+; CHECK: mov r10, r0
+; CHECK: bl {{_?}}swiftself_param
+define i8 *@call_swiftself(i8* %arg) {
+ %res = call i8 *@swiftself_param(i8* swiftself %arg)
+ ret i8 *%res
+}
-define void @simple_args() {
-; CHECK-APPLE-LABEL: simple_args:
-; CHECK-O0-LABEL: simple_args:
+; r10 should be saved by the callee even if used for swiftself
+; CHECK-LABEL: swiftself_clobber:
+; CHECK: push {r10}
+; ...
+; CHECK: pop {r10}
+define i8 *@swiftself_clobber(i8* swiftself %addr0) {
+ call void asm sideeffect "", "~{r10}"()
+ ret i8 *%addr0
+}
- call void @take_swiftself(i8* @var8_3)
-; CHECK-APPLE: add r9, pc
-; CHECK-APPLE: bl {{_?}}take_swiftself
-; CHECK-O0: add r9, pc
-; CHECK-O0: bl {{_?}}take_swiftself
-
+; Demonstrate that we do not need any movs when calling multiple functions
+; with swiftself argument.
+; CHECK-LABEL: swiftself_passthrough:
+; OPT-NOT: mov{{.*}}r10
+; OPT: bl {{_?}}swiftself_param
+; OPT-NOT: mov{{.*}}r10
+; OPT-NEXT: bl {{_?}}swiftself_param
+define void @swiftself_passthrough(i8* swiftself %addr0) {
+ call i8 *@swiftself_param(i8* swiftself %addr0)
+ call i8 *@swiftself_param(i8* swiftself %addr0)
ret void
}
+
+; We can use a tail call if the callee swiftself is the same as the caller one.
+; CHECK-LABEL: swiftself_tail:
+; TAILCALL: b {{_?}}swiftself_param
+; TAILCALL-NOT: pop
+define i8* @swiftself_tail(i8* swiftself %addr0) {
+ call void asm sideeffect "", "~{r10}"()
+ %res = tail call i8* @swiftself_param(i8* swiftself %addr0)
+ ret i8* %res
+}
+
+; We can not use a tail call if the callee swiftself is not the same as the
+; caller one.
+; CHECK-LABEL: swiftself_notail:
+; CHECK: mov r10, r0
+; CHECK: bl {{_?}}swiftself_param
+; CHECK: pop
+define i8* @swiftself_notail(i8* swiftself %addr0, i8* %addr1) nounwind {
+ %res = tail call i8* @swiftself_param(i8* swiftself %addr1)
+ ret i8* %res
+}