[TCWG CI] Regression caused by gcc: phiopt: Optimize partial_ordering spaceship
>= 0 -ffinite-math-only [PR94589]:
commit 65061ea287a80cfb214e402cfd2373a14bfec95a
Author: Jakub Jelinek <ja...@redhat.com>
phiopt: Optimize partial_ordering spaceship >= 0 -ffinite-math-only
[PR94589]
Results regressed to
# reset_artifacts:
-10
# build_abe binutils:
-9
# build_abe stage1:
-5
# build_abe qemu:
-2
# linux_n_obj:
33
# First few build errors in logs:
# 00:01:16 cc1plus: fatal error: ./include/generated/utsrelease.h: No such file
or directory
# 00:01:16 cc1plus: fatal error: ./include/generated/utsrelease.h: No such file
or directory
# 00:01:16 cc1plus: fatal error: ./include/generated/utsrelease.h: No such file
or directory
# 00:01:16 make[2]: *** [scripts/gcc-plugins/stackleak_plugin.so] Error 1
# 00:01:16 make[2]: *** [scripts/gcc-plugins/latent_entropy_plugin.so] Error 1
# 00:01:16 make[2]: *** [scripts/gcc-plugins/randomize_layout_plugin.so] Error 1
# 00:01:16 make[1]: *** [scripts/gcc-plugins] Error 2
# 00:01:17 make: *** [scripts] Error 2
from
# reset_artifacts:
-10
# build_abe binutils:
-9
# build_abe stage1:
-5
# build_abe qemu:
-2
# linux_n_obj:
21070
# linux build successful:
all
THIS IS THE END OF INTERESTING STUFF. BELOW ARE LINKS TO BUILDS, REPRODUCTION
INSTRUCTIONS, AND THE RAW COMMIT.
This commit has regressed these CI configurations:
- tcwg_kernel/gnu-release-aarch64-next-allyesconfig
First_bad build:
https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-release-aarch64-next-allyesconfig/138/artifact/artifacts/build-65061ea287a80cfb214e402cfd2373a14bfec95a/
Last_good build:
https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-release-aarch64-next-allyesconfig/138/artifact/artifacts/build-b2a09773155892e426b90ce8367e2ed6996b44ef/
Baseline build:
https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-release-aarch64-next-allyesconfig/138/artifact/artifacts/build-baseline/
Even more details:
https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-release-aarch64-next-allyesconfig/138/artifact/artifacts/
Reproduce builds:
<cut>
mkdir investigate-gcc-65061ea287a80cfb214e402cfd2373a14bfec95a
cd investigate-gcc-65061ea287a80cfb214e402cfd2373a14bfec95a
# Fetch scripts
git clone https://git.linaro.org/toolchain/jenkins-scripts
# Fetch manifests and test.sh script
mkdir -p artifacts/manifests
curl -o artifacts/manifests/build-baseline.sh
https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-release-aarch64-next-allyesconfig/138/artifact/artifacts/manifests/build-baseline.sh
--fail
curl -o artifacts/manifests/build-parameters.sh
https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-release-aarch64-next-allyesconfig/138/artifact/artifacts/manifests/build-parameters.sh
--fail
curl -o artifacts/test.sh
https://ci.linaro.org/job/tcwg_kernel-gnu-bisect-gnu-release-aarch64-next-allyesconfig/138/artifact/artifacts/test.sh
--fail
chmod +x artifacts/test.sh
# Reproduce the baseline build (build all pre-requisites)
./jenkins-scripts/tcwg_kernel-build.sh @@ artifacts/manifests/build-baseline.sh
# Save baseline build state (which is then restored in artifacts/test.sh)
mkdir -p ./bisect
rsync -a --del --delete-excluded --exclude /bisect/ --exclude /artifacts/
--exclude /gcc/ ./ ./bisect/baseline/
cd gcc
# Reproduce first_bad build
git checkout --detach 65061ea287a80cfb214e402cfd2373a14bfec95a
../artifacts/test.sh
# Reproduce last_good build
git checkout --detach b2a09773155892e426b90ce8367e2ed6996b44ef
../artifacts/test.sh
cd ..
</cut>
Full commit (up to 1000 lines):
<cut>
commit 65061ea287a80cfb214e402cfd2373a14bfec95a
Author: Jakub Jelinek <ja...@redhat.com>
Date: Tue May 18 10:08:51 2021 +0200
phiopt: Optimize partial_ordering spaceship >= 0 -ffinite-math-only
[PR94589]
As mentioned earlier, spaceship_replacement didn't optimize partial_ordering
>= 0 comparisons, because the possible values are -1, 0, 1, 2 and the
>= comparison is implemented as (res & 1) == res to choose the 0 and 1
cases from that. As we optimize that only with -ffinite-math-only, the
2 case is assumed not to happen and my earlier match.pd change optimizes
(res & 1) == res into (res & ~1) == 0, so this patch pattern matches
that case and handles it like res >= 0.
2021-05-18 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/94589
* tree-ssa-phiopt.c (spaceship_replacement): Pattern match
phi result used in (res & ~1) == 0 comparison as res >= 0 as
res == 2 would be UB with -ffinite-math-only.
* g++.dg/opt/pr94589-2.C: Adjust scan-tree-dump count from 14 to 12.
---
gcc/testsuite/g++.dg/opt/pr94589-2.C | 4 +-
gcc/tree-ssa-phiopt.c | 72 +++++++++++++++++++++++++++++++-----
2 files changed, 65 insertions(+), 11 deletions(-)
diff --git a/gcc/testsuite/g++.dg/opt/pr94589-2.C
b/gcc/testsuite/g++.dg/opt/pr94589-2.C
index dda947e22b1..e9ef84b1912 100644
--- a/gcc/testsuite/g++.dg/opt/pr94589-2.C
+++ b/gcc/testsuite/g++.dg/opt/pr94589-2.C
@@ -1,8 +1,8 @@
// PR tree-optimization/94589
// { dg-do compile { target c++20 } }
// { dg-options "-O2 -g0 -ffast-math -fdump-tree-optimized" }
-// { dg-final { scan-tree-dump-times "\[ij]_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=)
\[ij]_\[0-9]+\\(D\\)" 14 "optimized" } }
-// { dg-final { scan-tree-dump-times "i_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=)
5\\.0" 14 "optimized" } }
+// { dg-final { scan-tree-dump-times "\[ij]_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=)
\[ij]_\[0-9]+\\(D\\)" 12 "optimized" } }
+// { dg-final { scan-tree-dump-times "i_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=)
5\\.0" 12 "optimized" } }
#include <compare>
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index e0a41d41fba..8e8a08bc679 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -1887,8 +1887,9 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
edge e0, edge e1, gphi *phi,
tree arg0, tree arg1)
{
- if (!INTEGRAL_TYPE_P (TREE_TYPE (PHI_RESULT (phi)))
- || TYPE_UNSIGNED (TREE_TYPE (PHI_RESULT (phi)))
+ tree phires = PHI_RESULT (phi);
+ if (!INTEGRAL_TYPE_P (TREE_TYPE (phires))
+ || TYPE_UNSIGNED (TREE_TYPE (phires))
|| !tree_fits_shwi_p (arg0)
|| !tree_fits_shwi_p (arg1)
|| !IN_RANGE (tree_to_shwi (arg0), -1, 2)
@@ -1902,12 +1903,32 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
use_operand_p use_p;
gimple *use_stmt;
- if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (PHI_RESULT (phi)))
+ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (phires))
return false;
- if (!single_imm_use (PHI_RESULT (phi), &use_p, &use_stmt))
+ if (!single_imm_use (phires, &use_p, &use_stmt))
return false;
enum tree_code cmp;
tree lhs, rhs;
+ gimple *orig_use_stmt = use_stmt;
+ tree orig_use_lhs = NULL_TREE;
+ int prec = TYPE_PRECISION (TREE_TYPE (phires));
+ if (is_gimple_assign (use_stmt)
+ && gimple_assign_rhs_code (use_stmt) == BIT_AND_EXPR
+ && TREE_CODE (gimple_assign_rhs2 (use_stmt)) == INTEGER_CST
+ && (wi::to_wide (gimple_assign_rhs2 (use_stmt))
+ == wi::shifted_mask (1, prec - 1, false, prec)))
+ {
+ /* For partial_ordering result operator>= with unspec as second
+ argument is (res & 1) == res, folded by match.pd into
+ (res & ~1) == 0. */
+ orig_use_lhs = gimple_assign_lhs (use_stmt);
+ if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig_use_lhs))
+ return false;
+ if (EDGE_COUNT (phi_bb->preds) != 4)
+ return false;
+ if (!single_imm_use (orig_use_lhs, &use_p, &use_stmt))
+ return false;
+ }
if (gimple_code (use_stmt) == GIMPLE_COND)
{
cmp = gimple_cond_code (use_stmt);
@@ -1948,10 +1969,19 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
default:
return false;
}
- if (lhs != PHI_RESULT (phi)
+ if (lhs != (orig_use_lhs ? orig_use_lhs : phires)
|| !tree_fits_shwi_p (rhs)
|| !IN_RANGE (tree_to_shwi (rhs), -1, 1))
return false;
+ if (orig_use_lhs)
+ {
+ if ((cmp != EQ_EXPR && cmp != NE_EXPR) || !integer_zerop (rhs))
+ return false;
+ /* As for -ffast-math we assume the 2 return to be
+ impossible, canonicalize (res & ~1) == 0 into
+ res >= 0 and (res & ~1) != 0 as res < 0. */
+ cmp = cmp == EQ_EXPR ? GE_EXPR : LT_EXPR;
+ }
if (!empty_block_p (middle_bb))
return false;
@@ -2092,7 +2122,7 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
? EDGE_TRUE_VALUE : EDGE_FALSE_VALUE)) == 0)
return false;
- /* lhs1 one_cmp rhs1 results in PHI_RESULT (phi) of 1. */
+ /* lhs1 one_cmp rhs1 results in phires of 1. */
enum tree_code one_cmp;
if ((cmp1 == LT_EXPR)
^ (!integer_onep ((e1->flags & EDGE_TRUE_VALUE) ? arg1 : arg0)))
@@ -2185,13 +2215,29 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
use_operand_p use_p;
imm_use_iterator iter;
bool has_debug_uses = false;
- FOR_EACH_IMM_USE_FAST (use_p, iter, PHI_RESULT (phi))
+ FOR_EACH_IMM_USE_FAST (use_p, iter, phires)
{
gimple *use_stmt = USE_STMT (use_p);
+ if (orig_use_lhs && use_stmt == orig_use_stmt)
+ continue;
gcc_assert (is_gimple_debug (use_stmt));
has_debug_uses = true;
break;
}
+ if (orig_use_lhs)
+ {
+ if (!has_debug_uses)
+ FOR_EACH_IMM_USE_FAST (use_p, iter, orig_use_lhs)
+ {
+ gimple *use_stmt = USE_STMT (use_p);
+ gcc_assert (is_gimple_debug (use_stmt));
+ has_debug_uses = true;
+ }
+ gimple_stmt_iterator gsi = gsi_for_stmt (orig_use_stmt);
+ tree zero = build_zero_cst (TREE_TYPE (orig_use_lhs));
+ gimple_assign_set_rhs_with_ops (&gsi, INTEGER_CST, zero);
+ update_stmt (orig_use_stmt);
+ }
if (has_debug_uses)
{
@@ -2203,7 +2249,7 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
Ignore the value of 2, because if NaNs aren't expected,
all floating point numbers should be comparable. */
gimple_stmt_iterator gsi = gsi_after_labels (gimple_bb (phi));
- tree type = TREE_TYPE (PHI_RESULT (phi));
+ tree type = TREE_TYPE (phires);
tree temp1 = make_node (DEBUG_EXPR_DECL);
DECL_ARTIFICIAL (temp1) = 1;
TREE_TYPE (temp1) = type;
@@ -2221,10 +2267,18 @@ spaceship_replacement (basic_block cond_bb, basic_block
middle_bb,
t = build3 (COND_EXPR, type, t, build_zero_cst (type), temp1);
g = gimple_build_debug_bind (temp2, t, phi);
gsi_insert_before (&gsi, g, GSI_SAME_STMT);
- replace_uses_by (PHI_RESULT (phi), temp2);
+ replace_uses_by (phires, temp2);
+ if (orig_use_lhs)
+ replace_uses_by (orig_use_lhs, temp2);
}
}
+ if (orig_use_lhs)
+ {
+ gimple_stmt_iterator gsi = gsi_for_stmt (orig_use_stmt);
+ gsi_remove (&gsi, true);
+ }
+
gimple_stmt_iterator psi = gsi_for_stmt (phi);
remove_phi_node (&psi, true);
</cut>
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