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| author | Richard Biener <rguenther@suse.de> | 2023-07-27 13:08:32 +0200 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2023-07-27 15:55:18 +0200 |
| commit | d1c072a1c3411a6fe29900750b38210af8451eeb (patch) | |
| tree | 1be2c459b42d23ba8214bcaae402ffe2ecc3ccc7 /gcc | |
| parent | a426b91b27e28985f47d16827a532fbc28c09bd7 (diff) | |
| download | gcc-d1c072a1c3411a6fe29900750b38210af8451eeb.zip gcc-d1c072a1c3411a6fe29900750b38210af8451eeb.tar.gz gcc-d1c072a1c3411a6fe29900750b38210af8451eeb.tar.bz2 | |
tree-optimization/91838 - fix FAIL of g++.dg/opt/pr91838.C
The following fixes the lack of simplification of a vector shift
by an out-of-bounds shift value. For scalars this is done both
by CCP and VRP but vectors are not handled there. This results
in PR91838 differences in outcome dependent on whether a vector
shift ISA is available and thus vector lowering does or does not
expose scalar shifts here.
The following adds a match.pd pattern to catch uniform out-of-bound
shifts, simplifying them to zero when not sanitizing shift amounts.
PR tree-optimization/91838
* gimple-match-head.cc: Include attribs.h and asan.h.
* generic-match-head.cc: Likewise.
* match.pd (([rl]shift @0 out-of-bounds) -> zero): New pattern.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/generic-match-head.cc | 2 | ||||
| -rw-r--r-- | gcc/gimple-match-head.cc | 2 | ||||
| -rw-r--r-- | gcc/match.pd | 10 |
3 files changed, 14 insertions, 0 deletions
diff --git a/gcc/generic-match-head.cc b/gcc/generic-match-head.cc index b4b5bc8..a71c072 100644 --- a/gcc/generic-match-head.cc +++ b/gcc/generic-match-head.cc @@ -41,6 +41,8 @@ along with GCC; see the file COPYING3. If not see #include "tree-eh.h" #include "langhooks.h" #include "tree-pass.h" +#include "attribs.h" +#include "asan.h" /* Routine to determine if the types T1 and T2 are effectively the same for GENERIC. If T1 or T2 is not a type, the test diff --git a/gcc/gimple-match-head.cc b/gcc/gimple-match-head.cc index d795066..5d6d26d 100644 --- a/gcc/gimple-match-head.cc +++ b/gcc/gimple-match-head.cc @@ -47,6 +47,8 @@ along with GCC; see the file COPYING3. If not see #include "tm.h" #include "gimple-range.h" #include "langhooks.h" +#include "attribs.h" +#include "asan.h" tree do_valueize (tree, tree (*)(tree), bool &); tree do_valueize (tree (*)(tree), tree); diff --git a/gcc/match.pd b/gcc/match.pd index ab7622b..ee6cef6 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -1059,6 +1059,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) && tree_nop_conversion_p (type, TREE_TYPE (@1))) (lshift @0 @2))) +/* Shifts by precision or greater result in zero. */ +(for shift (lshift rshift) + (simplify + (shift @0 uniform_integer_cst_p@1) + (if ((GIMPLE || !sanitize_flags_p (SANITIZE_SHIFT_EXPONENT)) + /* Use a signed compare to leave negative shift counts alone. */ + && wi::ges_p (wi::to_wide (uniform_integer_cst_p (@1)), + element_precision (type))) + { build_zero_cst (type); }))) + /* Shifts by constants distribute over several binary operations, hence (X << C) + (Y << C) can be simplified to (X + Y) << C. */ (for op (plus minus) |