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MATCH: Improve zero_one_valued_p for cases without range information

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I noticed we sometimes lose range information in forwprop due to a few
match and simplify patterns optimizing away casts. So the easier way
to these cases is to add a match for zero_one_valued_p wich mathes
a cast from another zero_one_valued_p.
This also adds the case of `x & zero_one_valued_p` as being zero_one_valued_p
which allows catching more cases too.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

gcc/ChangeLog:

	* match.pd (zero_one_valued_p): Match a cast from a zero_one_valued_p.
	Also match `a & zero_one_valued_p` too.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/bool-13.c: Update testcase as we now do
	the MIN/MAX during forwprop1.
This commit is contained in:
Andrew Pinski 2023-09-14 14:47:04 -07:00
parent ba4c1f2bfc
commit b975c0dc3b
2 changed files with 15 additions and 10 deletions
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10
gcc/match.pd
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@ -2181,6 +2181,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
&& (TYPE_UNSIGNED (type)
|| TYPE_PRECISION (type) > 1))))
/* (a&1) is always [0,1] too. This is useful again when
the range is not known. */
(match zero_one_valued_p
(bit_and:c@0 @1 zero_one_valued_p))
/* A conversion from an zero_one_valued_p is still a [0,1].
This is useful when the range of a variable is not known */
(match zero_one_valued_p
(convert@0 zero_one_valued_p))
/* Transform { 0 or 1 } * { 0 or 1 } into { 0 or 1 } & { 0 or 1 }. */
(simplify
(mult zero_one_valued_p@0 zero_one_valued_p@1)

15
gcc/testsuite/gcc.dg/tree-ssa/bool-13.c
View file

@ -1,5 +1,5 @@
/* { dg-do compile } */
/* { dg-options "-O1 -fdump-tree-optimized -fdump-tree-original -fdump-tree-phiopt1 -fdump-tree-forwprop2" } */
/* { dg-options "-O1 -fdump-tree-optimized -fdump-tree-original -fdump-tree-forwprop1 -fdump-tree-forwprop2" } */
#define bool _Bool
int maxbool(bool ab, bool bb)
{
@ -22,15 +22,10 @@ int minbool(bool ab, bool bb)
/* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "original" } } */
/* { dg-final { scan-tree-dump-times "if " 0 "original" } } */
/* PHI-OPT1 should have kept it as min/max. */
/* { dg-final { scan-tree-dump-times "MAX_EXPR" 1 "phiopt1" } } */
/* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "phiopt1" } } */
/* { dg-final { scan-tree-dump-times "if " 0 "phiopt1" } } */
/* Forwprop2 (after ccp) will convert it into &\| */
/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "forwprop2" } } */
/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "forwprop2" } } */
/* { dg-final { scan-tree-dump-times "if " 0 "forwprop2" } } */
/* Forwprop1 will convert it into &\| as we can detect that the arguments are one_zero. */
/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "forwprop1" } } */
/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "forwprop1" } } */
/* { dg-final { scan-tree-dump-times "if " 0 "forwprop1" } } */
/* By optimize there should be no min/max nor if */
/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "optimized" } } */