llvm/test/CodeGen/ARM/2011-12-14-machine-sink.ll
Devang Patel 5211134fbd Do not sink instruction, if it is not profitable.
On ARM, peephole optimization for ABS creates a trivial cfg triangle which tempts machine sink to sink instructions in code which is really straight line code. Sometimes this sinking may alter register allocator input such that use and def of a reg is divided by a branch in between, which may result in extra spills. Now mahine sink avoids sinking if final sink destination is post dominator.

Radar 10266272.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146604 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-14 23:20:38 +00:00

49 lines
1.7 KiB
LLVM

; RUN: llc < %s -o /dev/null -stats |& FileCheck %s -check-prefix=STATS
; Radar 10266272
target datalayout = "e-p:32:32:32-i1:8:32-i8:8:32-i16:16:32-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:32:64-v128:32:128-a0:0:32-n32-S32"
target triple = "thumbv7-apple-ios4.0.0"
; STATS-NOT: machine-sink
define i32 @foo(i32 %h) nounwind readonly ssp {
entry:
br label %for.cond
for.cond: ; preds = %for.body, %entry
%cmp = icmp slt i32 0, %h
br i1 %cmp, label %for.body, label %if.end299
for.body: ; preds = %for.cond
%v.5 = select i1 undef, i32 undef, i32 0
%0 = load i8* undef, align 1, !tbaa !0
%conv88 = zext i8 %0 to i32
%sub89 = sub nsw i32 0, %conv88
%v.8 = select i1 undef, i32 undef, i32 %sub89
%1 = load i8* null, align 1, !tbaa !0
%conv108 = zext i8 %1 to i32
%2 = load i8* undef, align 1, !tbaa !0
%conv110 = zext i8 %2 to i32
%sub111 = sub nsw i32 %conv108, %conv110
%cmp112 = icmp slt i32 %sub111, 0
%sub115 = sub nsw i32 0, %sub111
%v.10 = select i1 %cmp112, i32 %sub115, i32 %sub111
%add62 = add i32 0, %v.5
%add73 = add i32 %add62, 0
%add84 = add i32 %add73, 0
%add95 = add i32 %add84, %v.8
%add106 = add i32 %add95, 0
%add117 = add i32 %add106, %v.10
%add128 = add i32 %add117, 0
%add139 = add i32 %add128, 0
%add150 = add i32 %add139, 0
%add161 = add i32 %add150, 0
%add172 = add i32 %add161, 0
br i1 undef, label %for.cond, label %if.end299
if.end299: ; preds = %for.body, %for.cond
%s.10 = phi i32 [ %add172, %for.body ], [ 0, %for.cond ]
ret i32 %s.10
}
!0 = metadata !{metadata !"omnipotent char", metadata !1}
!1 = metadata !{metadata !"Simple C/C++ TBAA", null}