https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107231
Bug ID: 107231
Summary: [13 Regression] c-c++-common/goacc/kernels-loop-g.c:
'-fcompare-debug' failure (length)
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Keywords: compare-debug-failure, openacc
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: tschwinge at gcc dot gnu.org
CC: erozen at microsoft dot com
Blocks: 104277
Target Milestone: ---
In a native x86_64-pc-linux-gnu build, when also running testing with '-m32'
('RUNTESTFLAGS="--target_board=unix\{,-m32\}"') I'm seeing a regression for
'-m32' (but not for default '-m64'):
[-PASS:-]{+FAIL:+} c-c++-common/goacc/kernels-loop-g.c (test for excess
errors)
PASS: c-c++-common/goacc/kernels-loop-g.c scan-tree-dump-not parloops1
"FAILED:"
PASS: c-c++-common/goacc/kernels-loop-g.c scan-tree-dump-times optimized
"(?n);; Function .*main._omp_fn.0" 1
PASS: c-c++-common/goacc/kernels-loop-g.c scan-tree-dump-times parloops1
"(?n)__attribute__\\(\\(oacc kernels parallelized, oacc function \\(, , \\),
oacc kernels, omp target entrypoint, noclone\\)\\)" 1
PASS: c-c++-common/goacc/kernels-loop-g.c scan-tree-dump-times parloops1
"SUCCESS: may be parallelized" 1
xgcc: error:
[...]/source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c:
'-fcompare-debug' failure (length)
That's for both C and C++ testing.
Note that this test case is a bit "degenerate" in that it needs
'-fcompare-debug' to compile (safe-guard; refer to PR100400).
Reproduce:
$ build-gcc/gcc/xgcc -Bbuild-gcc/gcc/
source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c -fopenacc
--param=openacc-kernels=decompose -O2 -g -S -fcompare-debug -m32 -save-temps
xgcc: error: source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop-g.c:
‘-fcompare-debug’ failure (length)
$ diff -u kernels-loop-g.c.gkd kernels-loop-g.gk.c.gkd
--- kernels-loop-g.c.gkd 2022-10-12 11:10:24.902809164 +0200
+++ kernels-loop-g.gk.c.gkd 2022-10-12 11:10:24.950809149 +0200
@@ -601,7 +601,7 @@
(set (reg/v:SI 0 ax [orig:96 i ] [96])
(const_int 0 [0]))
(clobber (reg:CC 17 flags))
- ])
"source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop.c":36:21 discrim 3#
{*movsi_xor}
+ ])
"source-gcc/gcc/testsuite/c-c++-common/goacc/kernels-loop.c":36:21#
{*movsi_xor}
(expr_list:REG_UNUSED (reg:CC 17 flags)
(nil)))
(code_label # 0 0 7 13 (nil) [1 uses])
The issue goes away if I revert commit
r13-3213-g80f414e6d73f9f1683f93d83ce63a6a482e54bee "Fix PR107193", commit
r13-3172-gf30e9fd33e56a5a721346ea6140722e1b193db42 "Set discriminators for call
stmts on the same line within the same basic block".
Alternatively, the issue goes away if I pass '-gno-statement-frontiers' (as I
found in the 'c-c++-common/ubsan/pr85213.c' hunk of commit
r13-2921-gf1adf45b17f7f1ede463524d80032bb2ec866ead "Add instruction level
discriminator support", referring to PR100733 "-fcompare-debug failure for
pr85213.c at -O1 -fdisable-tree-phiopt2"). If you confirm that this is indeed
what should currently be done, I'll push that flag onto
'c-c++-common/goacc/kernels-loop-g.c', for the time being?
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104277
[Bug 104277] [meta-bug] gstatement-frontiers causes fcompare-debug issues
