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| author | Richard Biener <rguenther@suse.de> | 2023-08-03 10:59:52 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2023-08-03 13:20:00 +0200 |
| commit | 3d48c11ad082def8ee237e5778d8a5d569bff96d (patch) | |
| tree | 9b254147c9b6be872a17208f62d62bf38b24935c | |
| parent | fab08d12b40ad637c5a4ce8e026fb43cd3f0fad1 (diff) | |
| download | gcc-3d48c11ad082def8ee237e5778d8a5d569bff96d.zip gcc-3d48c11ad082def8ee237e5778d8a5d569bff96d.tar.gz gcc-3d48c11ad082def8ee237e5778d8a5d569bff96d.tar.bz2 | |
Swap loop splitting and final value replacement
The following swaps the loop splitting pass and the final value
replacement pass to avoid keeping the IV of the earlier loop
live when not necessary. The existing gcc.target/i386/pr87007-5.c
testcase shows that we otherwise fail to elide an empty loop
later. I don't see any good reason why loop splitting would need
final value replacement, all exit values honor the constraints
we place on loop header PHIs automatically.
* passes.def: Exchange loop splitting and final value
replacement passes.
* gcc.target/i386/pr87007-5.c: Make sure we split the loop
and eliminate both in the end.
| -rw-r--r-- | gcc/passes.def | 2 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/pr87007-5.c | 4 |
2 files changed, 4 insertions, 2 deletions
diff --git a/gcc/passes.def b/gcc/passes.def index f2893ae..ef5a21a 100644 --- a/gcc/passes.def +++ b/gcc/passes.def @@ -282,8 +282,8 @@ along with GCC; see the file COPYING3. If not see form if possible. */ NEXT_PASS (pass_tree_loop_init); NEXT_PASS (pass_tree_unswitch); - NEXT_PASS (pass_scev_cprop); NEXT_PASS (pass_loop_split); + NEXT_PASS (pass_scev_cprop); NEXT_PASS (pass_loop_versioning); NEXT_PASS (pass_loop_jam); /* All unswitching, final value replacement and splitting can expose diff --git a/gcc/testsuite/gcc.target/i386/pr87007-5.c b/gcc/testsuite/gcc.target/i386/pr87007-5.c index b36e81c..a6cdf11 100644 --- a/gcc/testsuite/gcc.target/i386/pr87007-5.c +++ b/gcc/testsuite/gcc.target/i386/pr87007-5.c @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-Ofast -march=skylake-avx512 -mfpmath=sse -fno-tree-vectorize" } */ +/* { dg-options "-Ofast -march=skylake-avx512 -mfpmath=sse -fno-tree-vectorize -fdump-tree-cddce3-details -fdump-tree-lsplit-optimized" } */ /* Load of d2/d3 is hoisted out, vrndscalesd will reuse loades register to avoid partial dependence. */ #include<math.h> @@ -15,4 +15,6 @@ foo (int n, int k) d1 = sqrt (d3); } +/* { dg-final { scan-tree-dump "optimized: loop split" "lsplit" } } */ +/* { dg-final { scan-tree-dump-times "removing loop" 2 "cddce3" } } */ /* { dg-final { scan-assembler-times "vxorps\[^\n\r\]*xmm\[0-9\]" 0 } } */ |