* [PATCH] tree-ssa-loop-prefetch.cc: Honour -fno-unroll-loops
@ 2024-05-08 7:54 Stefan Schulze Frielinghaus
2024-05-08 8:32 ` Richard Biener
0 siblings, 1 reply; 2+ messages in thread
From: Stefan Schulze Frielinghaus @ 2024-05-08 7:54 UTC (permalink / raw)
To: gcc-patches; +Cc: Stefan Schulze Frielinghaus
On s390 the following tests fail
FAIL: gcc.dg/vect/pr109011-1.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .CLZ \\\\(vect" 1
FAIL: gcc.dg/vect/pr109011-1.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
FAIL: gcc.dg/vect/pr109011-1.c scan-tree-dump-times optimized " = .CLZ \\\\(vect" 1
FAIL: gcc.dg/vect/pr109011-1.c scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
FAIL: gcc.dg/vect/pr109011-2.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .CTZ \\\\(vect" 2
FAIL: gcc.dg/vect/pr109011-2.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
FAIL: gcc.dg/vect/pr109011-2.c scan-tree-dump-times optimized " = .CTZ \\\\(vect" 2
FAIL: gcc.dg/vect/pr109011-2.c scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
FAIL: gcc.dg/vect/pr109011-4.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .CTZ \\\\(vect" 2
FAIL: gcc.dg/vect/pr109011-4.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
FAIL: gcc.dg/vect/pr109011-4.c scan-tree-dump-times optimized " = .CTZ \\\\(vect" 2
FAIL: gcc.dg/vect/pr109011-4.c scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
because aprefetch unrolls loops even if -fno-unroll-loops is used.
Accordingly, the scan patterns match more than one time.
Could also be fixed by using -fno-prefetch-loop-arrays for the tests.
Though, I tend to prefer if aprefetch honours -fno-unroll-loops. Any
preferences?
Bootstrapped and regtested on x86_64 and s390. Ok for mainline?
gcc/ChangeLog:
* tree-ssa-loop-prefetch.cc (determine_unroll_factor): Honour
-fno-unroll-loops.
---
gcc/tree-ssa-loop-prefetch.cc | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/gcc/tree-ssa-loop-prefetch.cc b/gcc/tree-ssa-loop-prefetch.cc
index 70073cc4fe4..bb5d5dec779 100644
--- a/gcc/tree-ssa-loop-prefetch.cc
+++ b/gcc/tree-ssa-loop-prefetch.cc
@@ -1401,6 +1401,10 @@ determine_unroll_factor (class loop *loop, struct mem_ref_group *refs,
struct mem_ref_group *agp;
struct mem_ref *ref;
+ /* Bail out early in case we must not unroll loops. */
+ if (!flag_unroll_loops)
+ return 1;
+
/* First check whether the loop is not too large to unroll. We ignore
PARAM_MAX_UNROLL_TIMES, because for small loops, it prevented us
from unrolling them enough to make exactly one cache line covered by each
--
2.44.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] tree-ssa-loop-prefetch.cc: Honour -fno-unroll-loops
2024-05-08 7:54 [PATCH] tree-ssa-loop-prefetch.cc: Honour -fno-unroll-loops Stefan Schulze Frielinghaus
@ 2024-05-08 8:32 ` Richard Biener
0 siblings, 0 replies; 2+ messages in thread
From: Richard Biener @ 2024-05-08 8:32 UTC (permalink / raw)
To: Stefan Schulze Frielinghaus; +Cc: gcc-patches
On Wed, May 8, 2024 at 9:56 AM Stefan Schulze Frielinghaus
<stefansf@linux.ibm.com> wrote:
>
> On s390 the following tests fail
>
> FAIL: gcc.dg/vect/pr109011-1.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .CLZ \\\\(vect" 1
> FAIL: gcc.dg/vect/pr109011-1.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
> FAIL: gcc.dg/vect/pr109011-1.c scan-tree-dump-times optimized " = .CLZ \\\\(vect" 1
> FAIL: gcc.dg/vect/pr109011-1.c scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
> FAIL: gcc.dg/vect/pr109011-2.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .CTZ \\\\(vect" 2
> FAIL: gcc.dg/vect/pr109011-2.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
> FAIL: gcc.dg/vect/pr109011-2.c scan-tree-dump-times optimized " = .CTZ \\\\(vect" 2
> FAIL: gcc.dg/vect/pr109011-2.c scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
> FAIL: gcc.dg/vect/pr109011-4.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .CTZ \\\\(vect" 2
> FAIL: gcc.dg/vect/pr109011-4.c -flto -ffat-lto-objects scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
> FAIL: gcc.dg/vect/pr109011-4.c scan-tree-dump-times optimized " = .CTZ \\\\(vect" 2
> FAIL: gcc.dg/vect/pr109011-4.c scan-tree-dump-times optimized " = .POPCOUNT \\\\(vect" 1
>
> because aprefetch unrolls loops even if -fno-unroll-loops is used.
> Accordingly, the scan patterns match more than one time.
>
> Could also be fixed by using -fno-prefetch-loop-arrays for the tests.
> Though, I tend to prefer if aprefetch honours -fno-unroll-loops. Any
> preferences?
>
> Bootstrapped and regtested on x86_64 and s390. Ok for mainline?
OK.
Richard.
> gcc/ChangeLog:
>
> * tree-ssa-loop-prefetch.cc (determine_unroll_factor): Honour
> -fno-unroll-loops.
> ---
> gcc/tree-ssa-loop-prefetch.cc | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/gcc/tree-ssa-loop-prefetch.cc b/gcc/tree-ssa-loop-prefetch.cc
> index 70073cc4fe4..bb5d5dec779 100644
> --- a/gcc/tree-ssa-loop-prefetch.cc
> +++ b/gcc/tree-ssa-loop-prefetch.cc
> @@ -1401,6 +1401,10 @@ determine_unroll_factor (class loop *loop, struct mem_ref_group *refs,
> struct mem_ref_group *agp;
> struct mem_ref *ref;
>
> + /* Bail out early in case we must not unroll loops. */
> + if (!flag_unroll_loops)
> + return 1;
> +
> /* First check whether the loop is not too large to unroll. We ignore
> PARAM_MAX_UNROLL_TIMES, because for small loops, it prevented us
> from unrolling them enough to make exactly one cache line covered by each
> --
> 2.44.0
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2024-05-08 7:54 [PATCH] tree-ssa-loop-prefetch.cc: Honour -fno-unroll-loops Stefan Schulze Frielinghaus
2024-05-08 8:32 ` Richard Biener
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