llvm-6502/test/CodeGen/Thumb/copy_thumb.ll
Jonathan Roelofs 506ed4d4a5 Lower thumbv4t & thumbv5 lo->lo copies through a push-pop sequence
On pre-v6 hardware, 'MOV lo, lo' gives undefined results, so such copies need to
be avoided. This patch trades simplicity for implementation time at the expense
of performance... As they say: correctness first, then performance.

See http://lists.cs.uiuc.edu/pipermail/llvmdev/2014-August/075998.html for a few
ideas on how to make this better.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216138 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-20 23:38:50 +00:00

39 lines
1.7 KiB
LLVM

; RUN: llc -mtriple=armv4-none--eabi < %s | FileCheck %s --check-prefix=CHECK-LOLOMOV
; RUN: llc -mtriple=armv4t-none--eabi < %s | FileCheck %s --check-prefix=CHECK-LOLOMOV
; RUN: llc -mtriple=armv5-none--eabi < %s | FileCheck %s --check-prefix=CHECK-LOLOMOV
; RUN: llc -mtriple=armv6-none--eabi < %s | FileCheck %s --check-prefix=CHECK-LOLOMOV
; RUN: llc -mtriple=armv7-none--eabi < %s | FileCheck %s --check-prefix=CHECK-LOLOMOV
; RUN: llc -mtriple=thumbv6-none--eabi < %s | FileCheck %s --check-prefix=CHECK-LOLOMOV
; RUN: llc -mtriple=thumbv7-none--eabi < %s | FileCheck %s --check-prefix=CHECK-LOLOMOV
; CHECK-LOLOMOV-LABEL: foo
; CHECK-LOLOMOV: mov [[TMP:r[0-7]]], [[SRC1:r[01]]]
; CHECK-LOLOMOV-NEXT: mov [[SRC1]], [[SRC2:r[01]]]
; CHECK-LOLOMOV-NEXT: mov [[SRC2]], [[TMP]]
; CHECK-LOLOMOV-LABEL: bar
; CHECK-LOLOMOV-LABEL: fnend
;
; 'MOV lo, lo' in Thumb mode produces undefined results on pre-v6 hardware
; RUN: llc -mtriple=thumbv4t-none--eabi < %s | FileCheck %s --check-prefix=CHECK-NOLOLOMOV
; RUN: llc -mtriple=thumbv5-none--eabi < %s | FileCheck %s --check-prefix=CHECK-NOLOLOMOV
; CHECK-NOLOLOMOV-LABEL: foo
; CHECK-NOLOLOMOV-NOT: mov [[TMP:r[0-7]]], [[SRC1:r[01]]]
; CHECK-NOLOLOMOV: push {[[SRC1:r[01]]]}
; CHECK-NOLOLOMOV-NEXT: pop {[[TMP:r[0-7]]]}
; CHECK-NOLOLOMOV-NOT: mov [[TMP:r[0-7]]], [[SRC1:r[01]]]
; CHECK-NOLOLOMOV: push {[[SRC2:r[01]]]}
; CHECK-NOLOLOMOV-NEXT: pop {[[SRC1]]}
; CHECK-NOLOLOMOV-NOT: mov [[TMP:r[0-7]]], [[SRC1:r[01]]]
; CHECK-NOLOLOMOV: push {[[TMP]]}
; CHECK-NOLOLOMOV-NEXT: pop {[[SRC2]]}
; CHECK-NOLOLOMOV-LABEL: bar
; CHECK-NOLOLOMOV-LABEL: fnend
declare void @bar(i32, i32)
define void @foo(i32 %a, i32 %b) {
entry:
call void @bar(i32 %b, i32 %a);
ret void
}