[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456 --- Comment #7 from CVS Commits --- The trunk branch has been updated by Andrew Pinski : https://gcc.gnu.org/g:c3c6f30496d945b77dcb7f4ad8c3f8094f5a64a4 commit r14-4280-gc3c6f30496d945b77dcb7f4ad8c3f8094f5a64a4 Author: Andrew Pinski Date: Wed Sep 20 14:54:31 2023 -0700 MATCH: Simplify `(A ==/!= B) &/| (((cast)A) CMP C)` This patch adds support to the pattern for `(A == B) &/| (A CMP C)` where the second A could be casted to a different type. Some were handled correctly if using seperate `if` statements but not if combined with BIT_AND/BIT_IOR. In the case of pr111456-1.c, the testcase would pass if `--param=logical-op-non-short-circuit=0` was used but now can be optimized always. OK? Bootstrapped and tested on x86_64-linux-gnu. PR tree-optimization/106164 PR tree-optimization/111456 gcc/ChangeLog: * match.pd (`(A ==/!= B) & (A CMP C)`): Support an optional cast on the second A. (`(A ==/!= B) | (A CMP C)`): Likewise. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/cmpbit-6.c: New test. * gcc.dg/tree-ssa/cmpbit-7.c: New test. * gcc.dg/tree-ssa/pr111456-1.c: New test.
[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456 Andrew Pinski changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution|--- |FIXED --- Comment #8 from Andrew Pinski --- Fixed.
[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456 Andrew Pinski changed: What|Removed |Added URL||https://gcc.gnu.org/piperma ||il/gcc-patches/2023-Septemb ||er/631065.html Keywords||patch --- Comment #6 from Andrew Pinski --- Patch posted: https://gcc.gnu.org/pipermail/gcc-patches/2023-September/631065.html
[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456 --- Comment #5 from Andrew Pinski --- Just a quick note, --param=logical-op-non-short-circuit=0 also allows the missed optimization to no longer to be missed.
[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456 --- Comment #4 from Andrew Pinski --- Created attachment 55929 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55929=edit Patch which I am testing I still need to add testcases.
[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456
--- Comment #3 from Andrew Pinski ---
here is another missed optimization:
```
_Bool f2(int a, int b)
{
_Bool t = a == b;
unsigned t1 = a;
unsigned t2 = b;
_Bool b2 = t1 >= t2;
return t & b2;
}
```
This should just be optimized to `return a == b;`.
[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456
--- Comment #2 from Andrew Pinski ---
Reduced testcase for the missed optimization before and after the patch:
```
_Bool f(int a)
{
_Bool t = a == 0;
short t1 = a;
_Bool t2 = t1 >= 0;
return t & t2;
}
```
This really should just reduce to `return a == 0;`
[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456 Andrew Pinski changed: What|Removed |Added Ever confirmed|0 |1 Last reconfirmed||2023-09-18 Status|UNCONFIRMED |ASSIGNED Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot gnu.org --- Comment #1 from Andrew Pinski --- I noticed a few missed optimizations: [local count: 1073741824]: i.0_1 = i; _2 = (short int) i.0_1; _14 = _2 >= 0; _15 = i.0_1 == 0; _16 = _14 & _15; if (_16 != 0) goto ; [50.00%] else goto ; [50.00%] [local count: 805306368]: _21 = (int) _2; _20 = _21 == 0; _29 = _21 > 1; _30 = _20 | _29; if (_30 != 0) goto ; [72.67%] else goto ; [27.33%] Here this should have been just if (i.0_1 == 0) goto ; [50.00%] else goto ; [50.00%] And that would fix the rest. I suspect if we extend: /* Convert (X == CST1) && (X OP2 CST2) to a known value based on CST1 OP2 CST2. Similarly for (X != CST1). */ /* Convert (X == Y) && (X OP2 Y) to a known value if X is an integral type. Similarly for (X != Y). */ to handle a cast for the second part. This will be fixed ... Will handle that this weekend or earlier.
[Bug tree-optimization/111456] [14 Regression] Dead Code Elimination Regression since r14-3719-gb34f3736356
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111456 Richard Biener changed: What|Removed |Added Target Milestone|--- |14.0
