mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2025-02-01 13:11:39 +01:00
3fdcf4e64c
If a loop is not rotated (for example when optimizing for size), the latch is not the backedge. If we promote an expression to post-inc form, we not only increase register pressure and add a COPY for that IV expression but for all IVs!
Motivating testcase:
void f(float *a, float *b, float *c, int n) {
while (n-- > 0)
*c++ = *a++ + *b++;
}
It's imperative that the pointer increments be located in the latch block and not the header block; if not, we cannot use post-increment loads and stores and we have to keep both the post-inc and pre-inc values around until the end of the latch which bloats register usage.
llvm-svn: 278658
60 lines
2.3 KiB
LLVM
60 lines
2.3 KiB
LLVM
; RUN: llc -O3 -march=hexagon -mcpu=hexagonv5 < %s | FileCheck %s
|
|
; XFAIL: *
|
|
;
|
|
; Generate hardware loop when loop 'latch' block is different
|
|
; from the loop 'exiting' block.
|
|
|
|
; CHECK: loop0(.LBB{{.}}_{{.}}, r{{[0-9]+}})
|
|
; CHECK: endloop0
|
|
|
|
define void @test(i32* nocapture %pFL, i16 signext %nBS, i16* nocapture readonly %pHT) #0 {
|
|
entry:
|
|
%0 = load i32, i32* %pFL, align 4
|
|
%1 = tail call i64 @llvm.hexagon.M2.dpmpyss.s0(i32 %0, i32 246)
|
|
%2 = tail call i64 @llvm.hexagon.S2.asl.r.p(i64 %1, i32 -13)
|
|
%3 = tail call i32 @llvm.hexagon.A2.sat(i64 %2)
|
|
store i32 %3, i32* %pFL, align 4
|
|
%cmp16 = icmp sgt i16 %nBS, 0
|
|
br i1 %cmp16, label %for.body.lr.ph, label %for.end
|
|
|
|
for.body.lr.ph:
|
|
%4 = sext i16 %nBS to i32
|
|
br label %for.body
|
|
|
|
for.body:
|
|
%5 = phi i32 [ %3, %for.body.lr.ph ], [ %.pre, %for.body.for.body_crit_edge ]
|
|
%arrayidx3.phi = phi i32* [ %pFL, %for.body.lr.ph ], [ %arrayidx3.inc, %for.body.for.body_crit_edge ]
|
|
%arrayidx5.phi = phi i16* [ %pHT, %for.body.lr.ph ], [ %arrayidx5.inc, %for.body.for.body_crit_edge ]
|
|
%i.017.pmt = phi i32 [ 1, %for.body.lr.ph ], [ %phitmp, %for.body.for.body_crit_edge ]
|
|
%6 = load i16, i16* %arrayidx5.phi, align 2
|
|
%conv6 = sext i16 %6 to i32
|
|
%7 = tail call i64 @llvm.hexagon.M2.dpmpyss.s0(i32 %5, i32 %conv6)
|
|
%8 = tail call i64 @llvm.hexagon.S2.asl.r.p(i64 %7, i32 -13)
|
|
%9 = tail call i32 @llvm.hexagon.A2.sat(i64 %8)
|
|
store i32 %9, i32* %arrayidx3.phi, align 4
|
|
%exitcond = icmp eq i32 %i.017.pmt, %4
|
|
%arrayidx3.inc = getelementptr i32, i32* %arrayidx3.phi, i32 1
|
|
br i1 %exitcond, label %for.end.loopexit, label %for.body.for.body_crit_edge
|
|
|
|
for.body.for.body_crit_edge:
|
|
%arrayidx5.inc = getelementptr i16, i16* %arrayidx5.phi, i32 1
|
|
%.pre = load i32, i32* %arrayidx3.inc, align 4
|
|
%phitmp = add i32 %i.017.pmt, 1
|
|
br label %for.body
|
|
|
|
for.end.loopexit:
|
|
br label %for.end
|
|
|
|
for.end:
|
|
ret void
|
|
}
|
|
|
|
declare i32 @llvm.hexagon.A2.sat(i64) #1
|
|
|
|
declare i64 @llvm.hexagon.S2.asl.r.p(i64, i32) #1
|
|
|
|
declare i64 @llvm.hexagon.M2.dpmpyss.s0(i32, i32) #1
|
|
|
|
attributes #0 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf"="true" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "ssp-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
|
|
attributes #1 = { nounwind readnone }
|