[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195
--- Comment #11 from CVS Commits ---
The master branch has been updated by Thomas Schwinge :
https://gcc.gnu.org/g:a9de836c2b22f878cff592b96e11c1b95d4d36ee
commit r13-3434-ga9de836c2b22f878cff592b96e11c1b95d4d36ee
Author: Thomas Schwinge
Date: Sun Oct 16 00:07:20 2022 +0200
Restore 'libgomp.oacc-c-c++-common/nvptx-sese-1.c' SESE regions checking
[PR107195, PR107344]
That is, adjust for optimization introduced with recent
commit r13-3217-gc4d15dddf6b9eacb36f535807ad2ee364af46e04
"[PR107195] Set range to zero when nonzero mask is 0", where GCC now
understands that after 'r *= 2;', 'r & 1' will never hold here, and thus
transforms/optimizes/"disturbs" the original code such that GCC/nvptx's
later
"Neuter whole SESE regions" optimization no longer is applicable to it:
UNSUPPORTED: libgomp.oacc-c/../libgomp.oacc-c-c++-common/nvptx-sese-1.c
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none -O0
PASS: libgomp.oacc-c/../libgomp.oacc-c-c++-common/nvptx-sese-1.c
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none -O2 (test
for excess errors)
PASS: libgomp.oacc-c/../libgomp.oacc-c-c++-common/nvptx-sese-1.c
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none -O2
execution test
[-PASS:-]{+FAIL:+}
libgomp.oacc-c/../libgomp.oacc-c-c++-common/nvptx-sese-1.c
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none -O2
scan-nvptx-none-offload-rtl-dump mach "SESE regions:.*
[0-9]+{[0-9]+->[0-9]+(\\.[0-9]+)+}"
Same for C++.
It's unclear to me if this is an actual "problem", which optimization is
"more
important", so I've filed PR107344 "GCC/nvptx SESE region optimization" to
capture this question, and here restore what we intend to be testing (to my
understanding) in 'libgomp.oacc-c-c++-common/nvptx-sese-1.c'.
PR tree-optimization/107195
PR target/107344
libgomp/
* testsuite/libgomp.oacc-c-c++-common/nvptx-sese-1.c: Restore SESE
regions checking.
[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195 --- Comment #10 from CVS Commits --- The master branch has been updated by Thomas Schwinge : https://gcc.gnu.org/g:436c4a210e8ff936063579dab3641632c06c8a7d commit r13-3433-g436c4a210e8ff936063579dab3641632c06c8a7d Author: Thomas Schwinge Date: Mon Oct 17 09:10:03 2022 +0200 Add 'gcc.dg/tree-ssa/pr107195-3.c' [PR107195] ... to display optimization performed as of recent commit r13-3217-gc4d15dddf6b9eacb36f535807ad2ee364af46e04 "[PR107195] Set range to zero when nonzero mask is 0". PR tree-optimization/107195 gcc/testsuite/ * gcc.dg/tree-ssa/pr107195-3.c: New.
[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195 Martin Liška changed: What|Removed |Added CC||vsevolod.livinskiy at gmail dot co ||m --- Comment #9 from Martin Liška --- *** Bug 107228 has been marked as a duplicate of this bug. ***
[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195 Aldy Hernandez changed: What|Removed |Added Resolution|--- |FIXED Status|NEW |RESOLVED --- Comment #8 from Aldy Hernandez --- fixed
[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195 --- Comment #7 from CVS Commits --- The master branch has been updated by Aldy Hernandez : https://gcc.gnu.org/g:c4d15dddf6b9eacb36f535807ad2ee364af46e04 commit r13-3217-gc4d15dddf6b9eacb36f535807ad2ee364af46e04 Author: Aldy Hernandez Date: Mon Oct 10 20:42:10 2022 +0200 [PR107195] Set range to zero when nonzero mask is 0. When solving 0 = _15 & 1, we calculate _15 as: [irange] int [-INF, -2][0, +INF] NONZERO 0xfffe The known value of _15 is [0, 1] NONZERO 0x1 which is intersected with the above, yielding: [0, 1] NONZERO 0x0 This eventually gets copied to a _Bool [0, 1] NONZERO 0x0. This is problematic because here we have a bool which is zero, but returns false for irange::zero_p, since the latter does not look at nonzero bits. This causes logical_combine to assume the range is not-zero, and all hell breaks loose. I think we should just normalize a nonzero mask of 0 to [0, 0] at creation, thus avoiding all this. PR tree-optimization/107195 gcc/ChangeLog: * value-range.cc (irange::set_range_from_nonzero_bits): Set range to [0,0] when nonzero mask is 0. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/pr107195-1.c: New test. * gcc.dg/tree-ssa/pr107195-2.c: New test.
[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195 --- Comment #6 from Aldy Hernandez --- Created attachment 53687 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53687=edit untested patch
[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195 Aldy Hernandez changed: What|Removed |Added CC||amacleod at redhat dot com --- Comment #5 from Aldy Hernandez --- When solving 0 = _15 & 1, we calculate _15 as: [irange] int [-INF, -2][0, +INF] NONZERO 0xfffe The known value of _15 is [0, 1] NONZERO 0x1 which is intersected with the above, yielding: [0, 1] NONZERO 0x0 The final nonzero bits tells us the range is 0, but the range is still [0, 1], which causes logical_combine to assume the range is not-zero, as irange::zero_p() ignores the nonzero bits. I think we should just normalize a nonzero mask of 0 to [0, 0] at creation, thus avoiding all this.
[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195 --- Comment #4 from Aldy Hernandez --- *** Bug 107194 has been marked as a duplicate of this bug. ***
[Bug tree-optimization/107195] [13 Regression] wrong code with "-O1 -fno-tree-ccp" on x86_64-linux-gnu since r13-3090-gdf4c584c567263fd
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107195 Martin Liška changed: What|Removed |Added Keywords|needs-reduction | CC||aldyh at gcc dot gnu.org, ||marxin at gcc dot gnu.org See Also||https://gcc.gnu.org/bugzill ||a/show_bug.cgi?id=107194 Summary|[13 Regression] wrong code |[13 Regression] wrong code |with "-O1 -fno-tree-ccp" on |with "-O1 -fno-tree-ccp" on |x86_64-linux-gnu|x86_64-linux-gnu since ||r13-3090-gdf4c584c567263fd --- Comment #3 from Martin Liška --- Also started with r13-3090-gdf4c584c567263fd.
