This factors out some of the code from the min/max detection
from match.pd into a function so it can be reused in other
places. This is mainly used to detect the conversions
of >= to > which causes the integer values to be changed by
one.
OK? Bootstrapped and tested on x86_64-linux-gnu.
gcc/ChangeLog:
* match.pd: Factor out the deciding the min/max from
the "(cond (cmp (convert1? x) c1) (convert2? x) c2)"
pattern to ...
* fold-const.cc (minmax_from_comparison): this new function.
* fold-const.h (minmax_from_comparison): New prototype.
---
gcc/fold-const.cc | 43 +++++++++++++++++++++++++++++++++++++++++++
gcc/fold-const.h | 3 +++
gcc/match.pd | 29 +----------------------------
3 files changed, 47 insertions(+), 28 deletions(-)
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
index 3b397ae2941..b8add24f874 100644
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -150,6 +150,49 @@ static tree fold_convert_const (enum tree_code, tree,
tree);
static tree fold_view_convert_expr (tree, tree);
static tree fold_negate_expr (location_t, tree);
+/* This is a helper function to detect min/max for some operands of COND_EXPR.
+ The form is "(EXP0 CMP EXP1) ? EXP2 : EXP3". */
+tree_code
+minmax_from_comparison (tree_code cmp, tree exp0, tree exp1, tree exp2, tree
exp3)
+{
+ enum tree_code code = ERROR_MARK;
+
+ if (HONOR_NANS (exp0) || HONOR_SIGNED_ZEROS (exp0))
+ return ERROR_MARK;
+
+ if (!operand_equal_p (exp0, exp2))
+ return ERROR_MARK;
+
+ if (TREE_CODE (exp1) == INTEGER_CST && TREE_CODE (exp1) == INTEGER_CST
+ && wi::to_widest (exp1) == (wi::to_widest (exp3) - 1))
+ {
+ /* X <= Y - 1 equals to X < Y. */
+ if (cmp == LE_EXPR)
+ code = LT_EXPR;
+ /* X > Y - 1 equals to X >= Y. */
+ if (cmp == GT_EXPR)
+ code = GE_EXPR;
+ }
+ if (TREE_CODE (exp3) == INTEGER_CST && TREE_CODE (exp1) == INTEGER_CST
+ && wi::to_widest (exp1) == (wi::to_widest (exp3) + 1))
+ {
+ /* X < Y + 1 equals to X <= Y. */
+ if (cmp == LT_EXPR)
+ code = LE_EXPR;
+ /* X >= Y + 1 equals to X > Y. */
+ if (cmp == GE_EXPR)
+ code = GT_EXPR;
+ }
+ if (code != ERROR_MARK
+ || operand_equal_p (exp1, exp3))
+ {
+ if (cmp == LT_EXPR || cmp == LE_EXPR)
+ code = MIN_EXPR;
+ if (cmp == GT_EXPR || cmp == GE_EXPR)
+ code = MAX_EXPR;
+ }
+ return code;
+}
/* Return EXPR_LOCATION of T if it is not UNKNOWN_LOCATION.
Otherwise, return LOC. */
diff --git a/gcc/fold-const.h b/gcc/fold-const.h
index 56ecaa87fc6..b828badc42f 100644
--- a/gcc/fold-const.h
+++ b/gcc/fold-const.h
@@ -246,6 +246,9 @@ extern tree fold_build_pointer_plus_hwi_loc (location_t
loc, tree ptr, HOST_WIDE
#define fold_build_pointer_plus_hwi(p,o) \
fold_build_pointer_plus_hwi_loc (UNKNOWN_LOCATION, p, o)
+extern tree_code minmax_from_comparison (tree_code, tree, tree,
+ tree, tree);
+
/* In gimple-fold.cc. */
extern void clear_type_padding_in_mask (tree, unsigned char *);
extern bool clear_padding_type_may_have_padding_p (tree);
diff --git a/gcc/match.pd b/gcc/match.pd
index e89ba57e30b..6d3aaf45a93 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -4677,34 +4677,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
|| TYPE_SIGN (c2_type) == TYPE_SIGN (from_type)))))
{
if (cmp != EQ_EXPR)
- {
- if (wi::to_widest (@3) == (wi::to_widest (@2) - 1))
- {
- /* X <= Y - 1 equals to X < Y. */
- if (cmp == LE_EXPR)
- code = LT_EXPR;
- /* X > Y - 1 equals to X >= Y. */
- if (cmp == GT_EXPR)
- code = GE_EXPR;
- }
- if (wi::to_widest (@3) == (wi::to_widest (@2) + 1))
- {
- /* X < Y + 1 equals to X <= Y. */
- if (cmp == LT_EXPR)
- code = LE_EXPR;
- /* X >= Y + 1 equals to X > Y. */
- if (cmp == GE_EXPR)
- code = GT_EXPR;
- }
- if (code != ERROR_MARK
- || wi::to_widest (@2) == wi::to_widest (@3))
- {
- if (cmp == LT_EXPR || cmp == LE_EXPR)
- code = MIN_EXPR;
- if (cmp == GT_EXPR || cmp == GE_EXPR)
- code = MAX_EXPR;
- }
- }
+ code = minmax_from_comparison (cmp, @1, @3, @1, @2);
/* Can do A == C1 ? A : C2 -> A == C1 ? C1 : C2? */
else if (int_fits_type_p (@3, from_type))
code = EQ_EXPR;
--
2.39.1
