llvm-6502/test/CodeGen/Thumb/thumb-memcpy-ldm-stm.ll
Moritz Roth a6afad8b33 Thumb1 load/store optimizer: Improve code to materialize new base register.
There are two add-immediate instructions in Thumb1: tADDi8 and tADDi3. Only
the latter supports using different source and destination registers, so
whenever we materialize a new base register (at a certain offset) we'd do
so by moving the base register value to the new register and then adding in
place. This patch changes the code to use a single tADDi3 if the offset is
small enough to fit in 3 bits.

Differential Revision: http://reviews.llvm.org/D5006

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216193 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-21 17:11:03 +00:00

28 lines
809 B
LLVM

; RUN: llc -mtriple=thumbv6m-eabi -verify-machineinstrs %s -o - | FileCheck %s
@d = external global [64 x i32]
@s = external global [64 x i32]
; Function Attrs: nounwind
define void @t1() #0 {
entry:
; CHECK-LABEL: t1
; CHECK-NOT: ldm
; CHECK-NOT: stm
tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* bitcast ([64 x i32]* @s to i8*), i8* bitcast ([64 x i32]* @d to i8*), i32 17, i32 4, i1 false)
ret void
}
; Function Attrs: nounwind
define void @t2() #0 {
entry:
; CHECK-LABEL: t2:
; CHECK-NOT: ldm
; CHECK-NOT: stm
tail call void @llvm.memcpy.p0i8.p0i8.i32(i8* bitcast ([64 x i32]* @s to i8*), i8* bitcast ([64 x i32]* @d to i8*), i32 15, i32 4, i1 false)
ret void
}
; Function Attrs: nounwind
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture readonly, i32, i32, i1) #1