This patch adds the support for match that was implemented for PR 87913 in
phiopt.
It implements it by adding support to minmax_from_comparison for the check.
It uses the range information if available which allows to produce MIN/MAX
expression
when comparing against the lower/upper bound of the range instead of lower/upper
of the type.
minmax-20.c is the new testcase which tests the ranges part.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
gcc/ChangeLog:
* fold-const.cc (minmax_from_comparison): Add support for NE_EXPR.
* match.pd ((cond (cmp (convert1? x) c1) (convert2? x) c2) pattern):
Add ne as a possible cmp.
((a CMP b) ? minmax<a, c> : minmax<b, c> pattern): Likewise.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/minmax-20.c: New test.
---
gcc/fold-const.cc | 26 +++++++++++++++++++++++
gcc/match.pd | 4 ++--
gcc/testsuite/gcc.dg/tree-ssa/minmax-20.c | 12 +++++++++++
3 files changed, 40 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/minmax-20.c
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
index db54bfc5662..d90671b9975 100644
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -173,6 +173,19 @@ minmax_from_comparison (tree_code cmp, tree exp0, tree
exp1, tree exp2, tree exp
/* X > Y - 1 equals to X >= Y. */
if (cmp == GT_EXPR)
code = GE_EXPR;
+ /* a != MIN_RANGE<a> ? a : MIN_RANGE<a>+1 -> MAX_EXPR<MIN_RANGE<a>+1,
a> */
+ if (cmp == NE_EXPR && TREE_CODE (exp0) == SSA_NAME)
+ {
+ value_range r;
+ get_range_query (cfun)->range_of_expr (r, exp0);
+ if (r.undefined_p ())
+ r.set_varying (TREE_TYPE (exp0));
+
+ widest_int min = widest_int::from (r.lower_bound (),
+ TYPE_SIGN (TREE_TYPE (exp0)));
+ if (min == wi::to_widest (exp1))
+ code = MAX_EXPR;
+ }
}
if (wi::to_widest (exp1) == (wi::to_widest (exp3) + 1))
{
@@ -182,6 +195,19 @@ minmax_from_comparison (tree_code cmp, tree exp0, tree
exp1, tree exp2, tree exp
/* X >= Y + 1 equals to X > Y. */
if (cmp == GE_EXPR)
code = GT_EXPR;
+ /* a != MAX_RANGE<a> ? a : MAX_RANGE<a>-1 -> MIN_EXPR<MIN_RANGE<a>-1,
a> */
+ if (cmp == NE_EXPR && TREE_CODE (exp0) == SSA_NAME)
+ {
+ value_range r;
+ get_range_query (cfun)->range_of_expr (r, exp0);
+ if (r.undefined_p ())
+ r.set_varying (TREE_TYPE (exp0));
+
+ widest_int max = widest_int::from (r.upper_bound (),
+ TYPE_SIGN (TREE_TYPE (exp0)));
+ if (max == wi::to_widest (exp1))
+ code = MIN_EXPR;
+ }
}
}
if (code != ERROR_MARK
diff --git a/gcc/match.pd b/gcc/match.pd
index a55ede838cd..95f7e9a6abc 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -4751,7 +4751,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
Case 2)
(cond (eq (convert1? x) c1) (convert2? x) c2) -> (cond (eq x c1) c1 c2). */
-(for cmp (lt le gt ge eq)
+(for cmp (lt le gt ge eq ne)
(simplify
(cond (cmp (convert1? @1) INTEGER_CST@3) (convert2? @1) INTEGER_CST@2)
(with
@@ -4942,7 +4942,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* Optimize (a CMP b) ? minmax<a, c> : minmax<b, c>
to minmax<min/max<a, b>, c> */
(for minmax (min max)
- (for cmp (lt le gt ge)
+ (for cmp (lt le gt ge ne)
(simplify
(cond (cmp @1 @3) (minmax:c @1 @4) (minmax:c @2 @4))
(with
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/minmax-20.c
b/gcc/testsuite/gcc.dg/tree-ssa/minmax-20.c
new file mode 100644
index 00000000000..481c375f5f9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/minmax-20.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-phiopt2" } */
+
+int f(int num)
+{
+ if (num < 3) __builtin_unreachable();
+ return num != 3 ? num : 4;
+}
+
+/* In phiopt2 with the range information, this should be turned into
+ a MAX_EXPR. */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 1 "phiopt2" } } */
--
2.31.1
