From: liuhongt <hongtao.liu@intel.com>
To: gcc-patches@gcc.gnu.org
Subject: [PATCH] [RTL/fwprop] Allow propagations from inner loop to outer loop.
Date: Wed, 5 Jan 2022 13:38:51 +0800 [thread overview]
Message-ID: <20220105053851.55671-1-hongtao.liu@intel.com> (raw)
Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk.
gcc/ChangeLog:
PR rtl/103750
* cfgloop.h (loop_contains_p): New function.
* fwprop.c (forward_propagate_into): Allow propagations from
inner loop to outer loop.
gcc/testsuite/ChangeLog:
* g++.target/i386/pr103750-fwprop-1.C: New test.
---
gcc/cfgloop.h | 12 +++++++++
gcc/fwprop.c | 7 +++--
.../g++.target/i386/pr103750-fwprop-1.C | 26 +++++++++++++++++++
3 files changed, 43 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.target/i386/pr103750-fwprop-1.C
diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h
index d2714e20cb0..e8fe0cedd5f 100644
--- a/gcc/cfgloop.h
+++ b/gcc/cfgloop.h
@@ -908,6 +908,18 @@ loop_outermost (class loop *loop)
return (*loop->superloops)[1];
}
+/* Returns true if loop OUTER contains loop INNER. */
+static inline bool
+loop_contains_p (class loop* outer, class loop* inner)
+{
+ unsigned n = vec_safe_length (inner->superloops);
+
+ for (unsigned i = 0; i != n; i++)
+ if ((*inner->superloops)[i] == outer)
+ return true;
+ return false;
+}
+
extern void record_niter_bound (class loop *, const widest_int &, bool, bool);
extern HOST_WIDE_INT get_estimated_loop_iterations_int (class loop *);
extern HOST_WIDE_INT get_max_loop_iterations_int (const class loop *);
diff --git a/gcc/fwprop.c b/gcc/fwprop.c
index 2eab4fd4614..aed48e7273f 100644
--- a/gcc/fwprop.c
+++ b/gcc/fwprop.c
@@ -866,10 +866,13 @@ forward_propagate_into (use_info *use, bool reg_prop_only = false)
rtx src = SET_SRC (def_set);
/* Allow propagations into a loop only for reg-to-reg copies, since
- replacing one register by another shouldn't increase the cost. */
+ replacing one register by another shouldn't increase the cost.
+ Propagations from inner loop to outer loop should be also ok. */
struct loop *def_loop = def_insn->bb ()->cfg_bb ()->loop_father;
struct loop *use_loop = use->bb ()->cfg_bb ()->loop_father;
- if ((reg_prop_only || def_loop != use_loop)
+ if ((reg_prop_only
+ || (use_loop && def_loop != use_loop
+ && !loop_contains_p (use_loop, def_loop)))
&& (!reg_single_def_p (dest) || !reg_single_def_p (src)))
return false;
diff --git a/gcc/testsuite/g++.target/i386/pr103750-fwprop-1.C b/gcc/testsuite/g++.target/i386/pr103750-fwprop-1.C
new file mode 100644
index 00000000000..26987d307aa
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr103750-fwprop-1.C
@@ -0,0 +1,26 @@
+/* PR target/103750. */
+/* { dg-do compile } */
+/* { dg-options "-O2 -std=c++1y -march=cannonlake -fdump-rtl-fwprop1" } */
+/* { dg-final { scan-rtl-dump-not "subreg:HI\[ \\\(\]*reg:SI\[^\n]*\n\[^\n]*UNSPEC_TZCNT" "fwprop1" } } */
+
+#include<immintrin.h>
+const char16_t *qustrchr(char16_t *n, char16_t *e, char16_t c) noexcept
+{
+ __m256i mch256 = _mm256_set1_epi16(c);
+ for ( ; n < e; n += 32) {
+ __m256i data1 = _mm256_loadu_si256(reinterpret_cast<const __m256i *>(n));
+ __m256i data2 = _mm256_loadu_si256(reinterpret_cast<const __m256i *>(n) + 1);
+ __mmask16 mask1 = _mm256_cmpeq_epu16_mask(data1, mch256);
+ __mmask16 mask2 = _mm256_cmpeq_epu16_mask(data2, mch256);
+ if (_kortestz_mask16_u8(mask1, mask2))
+ continue;
+
+ unsigned idx = _tzcnt_u32(mask1);
+ if (mask1 == 0) {
+ idx = __tzcnt_u16(mask2);
+ n += 16;
+ }
+ return n + idx;
+ }
+ return e;
+}
--
2.18.1
next reply other threads:[~2022-01-05 5:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-05 5:38 liuhongt [this message]
2022-01-05 8:07 ` Richard Biener
2022-01-06 6:51 ` liuhongt
2022-01-06 10:55 ` Richard Biener
2022-01-07 5:16 ` liuhongt
2022-01-07 12:00 ` Richard Sandiford
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