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* [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs @ 2022-03-01 11:02 ro at gcc dot gnu.org 2022-03-01 11:04 ` [Bug target/104732] " ro at gcc dot gnu.org ` (7 more replies) 0 siblings, 8 replies; 9+ messages in thread From: ro at gcc dot gnu.org @ 2022-03-01 11:02 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 Bug ID: 104732 Summary: gcc.target/i386/pr100711-1.c FAILs Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: ro at gcc dot gnu.org CC: sayle at gcc dot gnu.org Target Milestone: --- Target: i?86-pc-solaris2.11, x86_64-pc-solaris2.11 The gcc.target/i386/pr100711-1.c test FAILs on 32-bit Solaris/x86: FAIL: gcc.target/i386/pr100711-1.c scan-assembler-times pandn 2 The pattern occurs only once. Attaching assembler output. ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/104732] gcc.target/i386/pr100711-1.c FAILs 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org @ 2022-03-01 11:04 ` ro at gcc dot gnu.org 2022-03-01 11:04 ` ro at gcc dot gnu.org ` (6 subsequent siblings) 7 siblings, 0 replies; 9+ messages in thread From: ro at gcc dot gnu.org @ 2022-03-01 11:04 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 --- Comment #1 from Rainer Orth <ro at gcc dot gnu.org> --- Created attachment 52534 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52534&action=edit 32-bit i386-pc-solaris2.11 pr100711-1.s ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/104732] gcc.target/i386/pr100711-1.c FAILs 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org 2022-03-01 11:04 ` [Bug target/104732] " ro at gcc dot gnu.org @ 2022-03-01 11:04 ` ro at gcc dot gnu.org 2022-03-01 13:57 ` jakub at gcc dot gnu.org ` (5 subsequent siblings) 7 siblings, 0 replies; 9+ messages in thread From: ro at gcc dot gnu.org @ 2022-03-01 11:04 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 Rainer Orth <ro at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |12.0 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/104732] gcc.target/i386/pr100711-1.c FAILs 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org 2022-03-01 11:04 ` [Bug target/104732] " ro at gcc dot gnu.org 2022-03-01 11:04 ` ro at gcc dot gnu.org @ 2022-03-01 13:57 ` jakub at gcc dot gnu.org 2022-03-01 15:23 ` ro at CeBiTec dot Uni-Bielefeld.DE ` (4 subsequent siblings) 7 siblings, 0 replies; 9+ messages in thread From: jakub at gcc dot gnu.org @ 2022-03-01 13:57 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- The reason is that in order to match pandn in bar, it relies on the stv pass being done, and TARGET_STV is disabled if -mpreferred-stack-boundary={2,3}, or -mincoming-stack-boundatry={2,3} or -mstackrealign. The last one is what matters on Solaris (and on cygming too?), because those define STACK_REALIGN_DEFAULT to non-zero. I'd say we should just add -mno-stackrealign to dg-options in that testcase. ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug target/104732] gcc.target/i386/pr100711-1.c FAILs 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org ` (2 preceding siblings ...) 2022-03-01 13:57 ` jakub at gcc dot gnu.org @ 2022-03-01 15:23 ` ro at CeBiTec dot Uni-Bielefeld.DE 2022-03-04 12:16 ` [Bug testsuite/104732] " roger at nextmovesoftware dot com ` (3 subsequent siblings) 7 siblings, 0 replies; 9+ messages in thread From: ro at CeBiTec dot Uni-Bielefeld.DE @ 2022-03-01 15:23 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 --- Comment #3 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> --- > --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- [...] > I'd say we should just add -mno-stackrealign to dg-options in that testcase. That works indeed. We already had several instances of this issue in the past. ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug testsuite/104732] gcc.target/i386/pr100711-1.c FAILs 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org ` (3 preceding siblings ...) 2022-03-01 15:23 ` ro at CeBiTec dot Uni-Bielefeld.DE @ 2022-03-04 12:16 ` roger at nextmovesoftware dot com 2022-03-05 8:52 ` cvs-commit at gcc dot gnu.org ` (2 subsequent siblings) 7 siblings, 0 replies; 9+ messages in thread From: roger at nextmovesoftware dot com @ 2022-03-04 12:16 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 Roger Sayle <roger at nextmovesoftware dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |roger at nextmovesoftware dot com Last reconfirmed| |2022-03-04 Ever confirmed|0 |1 Status|UNCONFIRMED |ASSIGNED Assignee|unassigned at gcc dot gnu.org |roger at nextmovesoftware dot com --- Comment #4 from Roger Sayle <roger at nextmovesoftware dot com> --- Mine. Currently boostrapping and regression testing Uros' suggested improvements to my patch at https://gcc.gnu.org/pipermail/gcc-patches/2022-March/591199.html. ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug testsuite/104732] gcc.target/i386/pr100711-1.c FAILs 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org ` (4 preceding siblings ...) 2022-03-04 12:16 ` [Bug testsuite/104732] " roger at nextmovesoftware dot com @ 2022-03-05 8:52 ` cvs-commit at gcc dot gnu.org 2022-03-09 16:07 ` roger at nextmovesoftware dot com 2022-03-11 8:59 ` ro at CeBiTec dot Uni-Bielefeld.DE 7 siblings, 0 replies; 9+ messages in thread From: cvs-commit at gcc dot gnu.org @ 2022-03-05 8:52 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 --- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Roger Sayle <sayle@gcc.gnu.org>: https://gcc.gnu.org/g:8ea4a34bd0b0a46277b5e077c89cbd86dfb09c48 commit r12-7502-g8ea4a34bd0b0a46277b5e077c89cbd86dfb09c48 Author: Roger Sayle <roger@nextmovesoftware.com> Date: Sat Mar 5 08:50:45 2022 +0000 PR 104732: Simplify/fix DI mode logic expansion/splitting on -m32. This clean-up patch resolves PR testsuite/104732, the failure of the recent test gcc.target/i386/pr100711-1.c on 32-bit Solaris/x86. Rather than just tweak the testcase, the proposed approach is to fix the underlying problem by removing the "TARGET_STV && TARGET_SSE2" conditionals from the DI mode logical operation expanders and pre-reload splitters in i386.md, which as I'll show generate inferior code (even a GCC 12 regression) on !TARGET_64BIT whenever -mno-stv (such as Solaris) or -msse (but not -msse2). First a little bit of history. In the beginning, DImode operations on i386 weren't defined by the machine description, and lowered during RTL expansion to SI mode operations. The with PR 65105 in 2015, -mstv was added, together with a SWIM1248x mode iterator (later renamed to SWIM1248x) together with several *<code>di3_doubleword post-reload splitters that made use of register allocation to perform some double word operations in 64-but XMM registers. A short while later in 2016, PR 70322 added similar support for one_cmpldi2. All of this logic was dependent upon "!TARGET_64BIT && TARGET_STV && TARGET_SSE2". With the passing of time, these conditions became irrelevant when in 2019, it was decided to split these double-word patterns before reload. https://gcc.gnu.org/pipermail/gcc-patches/2019-June/523877.html https://gcc.gnu.org/pipermail/gcc-patches/2019-October/532236.html Hence the current situation, where on most modern CPU architectures (where "TARGET_STV && TARGET_SSE2" is true), RTL is expanded with DI mode operations, that are then split into two SI mode instructions before reload, except on Solaris and other odd cases, where the splitting is to two SI mode instructions is done during RTL expansion. By the time compilation reaches register allocation both paths in theory produce identical or similar code, so the vestigial legacy/logic would appear to be harmless. Unfortunately, there is one place where this arbitrary choice of how to lower DI mode doubleword operations is visible to the middle-end, it controls whether the backend appears to have a suitable optab, and the presence (or not) of DImode optabs can influence vectorization cost models and veclower decisions. The issue (and code quality regression) can be seen in this test case: typedef long long v2di __attribute__((vector_size (16))); v2di x; void foo (long long a) { v2di t = {a, a}; x = ~t; } which when compiled with "-O2 -m32 -msse -march=pentiumpro" produces: foo: subl $28, %esp movl %ebx, 16(%esp) movl 32(%esp), %eax movl %esi, 20(%esp) movl 36(%esp), %edx movl %edi, 24(%esp) movl %eax, %esi movl %eax, %edi movl %edx, %ebx movl %edx, %ecx notl %esi notl %ebx movl %esi, (%esp) notl %edi notl %ecx movl %ebx, 4(%esp) movl 20(%esp), %esi movl %edi, 8(%esp) movl 16(%esp), %ebx movl %ecx, 12(%esp) movl 24(%esp), %edi movss 8(%esp), %xmm1 movss 12(%esp), %xmm2 movss (%esp), %xmm0 movss 4(%esp), %xmm3 unpcklps %xmm2, %xmm1 unpcklps %xmm3, %xmm0 movlhps %xmm1, %xmm0 movaps %xmm0, x addl $28, %esp ret Importantly notice the four "notl" instructions. With this patch: foo: subl $28, %esp movl 32(%esp), %edx movl 36(%esp), %eax notl %edx movl %edx, (%esp) notl %eax movl %eax, 4(%esp) movl %edx, 8(%esp) movl %eax, 12(%esp) movaps (%esp), %xmm1 movaps %xmm1, x addl $28, %esp ret Notice only two "notl" instructions. Checking with godbolt.org, GCC generated 4 NOTs in GCC 4.x and 5.x, 2 NOTs between GCC 6.x and 9.x, and regressed to 4 NOTs since GCC 10.x [which hopefully qualifies this clean-up as suitable for stage 4]. Most significantly, this patch allows pr100711-1.c to pass with -mno-stv, allowing pandn to be used with V2DImode on Solaris/x86. Fingers-crossed this should reduce the number of discrepancies encountered supporting Solaris/x86. 2022-03-05 Roger Sayle <roger@nextmovesoftware.com> Uroš Bizjak <ubizjak@gmail.com> gcc/ChangeLog PR testsuite/104732 * config/i386/i386.md (SWIM1248x): Renamed from SWIM1248s. Include DI mode unconditionally. (*anddi3_doubleword): Remove && TARGET_STV && TARGET_SSE2 condition, i.e. always split on !TARGET_64BIT. (*<any_or>di3_doubleword): Likewise. (*one_cmpldi2_doubleword): Likewise. (and<mode>3 expander): Update to use SWIM1248x from SWIM1248s. (<any_or><mode>3 expander): Likewise. (one_cmpl<mode>2 expander): Likewise. gcc/testsuite/ChangeLog PR testsuite/104732 * gcc.target/i386/pr104732.c: New test case. ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug testsuite/104732] gcc.target/i386/pr100711-1.c FAILs 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org ` (5 preceding siblings ...) 2022-03-05 8:52 ` cvs-commit at gcc dot gnu.org @ 2022-03-09 16:07 ` roger at nextmovesoftware dot com 2022-03-11 8:59 ` ro at CeBiTec dot Uni-Bielefeld.DE 7 siblings, 0 replies; 9+ messages in thread From: roger at nextmovesoftware dot com @ 2022-03-09 16:07 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 Roger Sayle <roger at nextmovesoftware dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution|--- |FIXED --- Comment #6 from Roger Sayle <roger at nextmovesoftware dot com> --- This should now be fixed on mainline. Rainer please let me know if you notice any remaining issues on solaris/x86. ^ permalink raw reply [flat|nested] 9+ messages in thread
* [Bug testsuite/104732] gcc.target/i386/pr100711-1.c FAILs 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org ` (6 preceding siblings ...) 2022-03-09 16:07 ` roger at nextmovesoftware dot com @ 2022-03-11 8:59 ` ro at CeBiTec dot Uni-Bielefeld.DE 7 siblings, 0 replies; 9+ messages in thread From: ro at CeBiTec dot Uni-Bielefeld.DE @ 2022-03-11 8:59 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104732 --- Comment #7 from ro at CeBiTec dot Uni-Bielefeld.DE <ro at CeBiTec dot Uni-Bielefeld.DE> --- > --- Comment #6 from Roger Sayle <roger at nextmovesoftware dot com> --- > This should now be fixed on mainline. Rainer please let me know if you notice > any remaining issues on solaris/x86. I've now run bootstraps with and without your patch: no regressions apart from the usual flakey tests. Thanks! ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2022-03-11 8:59 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-03-01 11:02 [Bug target/104732] New: gcc.target/i386/pr100711-1.c FAILs ro at gcc dot gnu.org 2022-03-01 11:04 ` [Bug target/104732] " ro at gcc dot gnu.org 2022-03-01 11:04 ` ro at gcc dot gnu.org 2022-03-01 13:57 ` jakub at gcc dot gnu.org 2022-03-01 15:23 ` ro at CeBiTec dot Uni-Bielefeld.DE 2022-03-04 12:16 ` [Bug testsuite/104732] " roger at nextmovesoftware dot com 2022-03-05 8:52 ` cvs-commit at gcc dot gnu.org 2022-03-09 16:07 ` roger at nextmovesoftware dot com 2022-03-11 8:59 ` ro at CeBiTec dot Uni-Bielefeld.DE
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