Explicitly request physreg coalesing for a bunch of Thumb2 unit tests.

These tests all follow the same pattern:

	mov	r2, r0
	movs	r0, #0
	$CMP	r2, r1
	it	eq
	moveq	r0, #1
	bx	lr

The first 'mov' can be eliminated by rematerializing 'movs r0, #0' below the
test instruction:

	$CMP	r0, r1
	mov.w	r0, #0
	it	eq
	moveq	r0, #1
	bx	lr

So far, only physreg coalescing can do that. The register allocators won't yet
split live ranges just to eliminate copies. They can learn, but this particular
problem is not likely to show up in real code. It only appears because r0 is
used for both the function argument and return value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130858 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2011-05-04 19:02:07 +00:00
parent 21f7902a89
commit 28e104bcb0
7 changed files with 26 additions and 7 deletions

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@ -1,4 +1,7 @@
; RUN: llc < %s -march=thumb -mattr=+thumb2 | FileCheck %s
; RUN: llc < %s -march=thumb -mattr=+thumb2 -join-physregs | FileCheck %s
; These tests implicitly depend on 'movs r0, #0' being rematerialized below the
; test as 'mov.w r0, #0'. So far, that requires physreg joining.
define i1 @f1(i32 %a, i32 %b) {
%nb = sub i32 0, %b

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@ -1,4 +1,7 @@
; RUN: llc < %s -march=thumb -mattr=+thumb2 | FileCheck %s
; RUN: llc < %s -march=thumb -mattr=+thumb2 -join-physregs | FileCheck %s
; These tests implicitly depend on 'movs r0, #0' being rematerialized below the
; test as 'mov.w r0, #0'. So far, that requires physreg joining.
; 0x000000bb = 187
define i1 @f1(i32 %a) {

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@ -1,4 +1,7 @@
; RUN: llc < %s -march=thumb -mattr=+thumb2 | FileCheck %s
; RUN: llc < %s -march=thumb -mattr=+thumb2 -join-physregs | FileCheck %s
; These tests implicitly depend on 'movs r0, #0' being rematerialized below the
; test as 'mov.w r0, #0'. So far, that requires physreg joining.
define i1 @f1(i32 %a, i32 %b) {
; CHECK: f1:

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@ -1,5 +1,7 @@
; RUN: llc < %s -march=thumb -mattr=+thumb2 | FileCheck %s
; RUN: llc < %s -march=thumb -mattr=+thumb2 -join-physregs | FileCheck %s
; These tests implicitly depend on 'movs r0, #0' being rematerialized below the
; test as 'mov.w r0, #0'. So far, that requires physreg joining.
; 0x000000bb = 187
define i1 @f1(i32 %a) {

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@ -1,4 +1,7 @@
; RUN: llc < %s -march=thumb -mattr=+thumb2 | FileCheck %s
; RUN: llc < %s -march=thumb -mattr=+thumb2 -join-physregs | FileCheck %s
; These tests implicitly depend on 'movs r0, #0' being rematerialized below the
; tst as 'mov.w r0, #0'. So far, that requires physreg joining.
define i1 @f1(i32 %a, i32 %b) {
; CHECK: f1

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@ -1,5 +1,7 @@
; RUN: llc < %s -march=thumb -mattr=+thumb2 | FileCheck %s
; RUN: llc < %s -march=thumb -mattr=+thumb2 -join-physregs | FileCheck %s
; These tests implicitly depend on 'movs r0, #0' being rematerialized below the
; tst as 'mov.w r0, #0'. So far, that requires physreg joining.
; 0x000000bb = 187
define i1 @f1(i32 %a) {

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@ -1,4 +1,7 @@
; RUN: llc < %s -march=thumb -mattr=+thumb2 | FileCheck %s
; RUN: llc < %s -march=thumb -mattr=+thumb2 -join-physregs | FileCheck %s
; These tests implicitly depend on 'movs r0, #0' being rematerialized below the
; tst as 'mov.w r0, #0'. So far, that requires physreg joining.
define i1 @f1(i32 %a, i32 %b) {
; CHECK: f1: