The following adds MIN/MAX folding from fold_cond_expr_with_comparison
to the part GIMPLE of match.pd, leaving the GENERIC part in
fold-const.cc since that's constrainted on frontend specific things
I did not want to carry to match.pd.
The effect becomes appearant when we no longer can rely on GENERIC
folding of COND_EXPRs in gcc.dg/tree-ssa/pr92834.c and
gcc.dg/tree-ssa/pr94786.c.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Richard.
2022-05-13 Richard Biener <rguent...@suse.de>
* match.pd (A cmp B ? A : B -> min/max): New patterns
carried over from fold_cond_expr_with_comparison.
---
gcc/match.pd | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/gcc/match.pd b/gcc/match.pd
index f5efa77560c..0995055fcb5 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -4450,6 +4450,52 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(op (min @X { wide_int_to_tree (from_type, real_c1); })
{ wide_int_to_tree (from_type, c2); })))))))))
+#if GIMPLE
+/* A >= B ? A : B -> max (A, B) and friends. The code is still
+ in fold_cond_expr_with_comparison for GENERIC folding with
+ some extra constraints. */
+(for cmp (eq ne le lt unle unlt ge gt unge ungt uneq ltgt)
+ (simplify
+ (cond (cmp:c (nop_convert1?@c0 @0) (nop_convert2?@c1 @1))
+ (convert3? @0) (convert4? @1))
+ (if (!HONOR_SIGNED_ZEROS (type)
+ && ((INTEGRAL_TYPE_P (type)
+ /* Allow widening conversions of the data. */
+ && TYPE_PRECISION (TREE_TYPE (@0)) <= TYPE_PRECISION (type)
+ && TYPE_PRECISION (TREE_TYPE (@1)) <= TYPE_PRECISION (type))
+ || (tree_nop_conversion_p (type, TREE_TYPE (@0))
+ && tree_nop_conversion_p (type, TREE_TYPE (@1)))))
+ (switch
+ (if (cmp == EQ_EXPR)
+ (if (VECTOR_TYPE_P (type))
+ (view_convert @c1)
+ (convert @c1)))
+ (if (cmp == NE_EXPR)
+ (if (VECTOR_TYPE_P (type))
+ (view_convert @c0)
+ (convert @c0)))
+ (if (cmp == LE_EXPR || cmp == UNLE_EXPR || cmp == LT_EXPR || cmp ==
UNLT_EXPR)
+ (if (!HONOR_NANS (type))
+ (if (VECTOR_TYPE_P (type))
+ (view_convert (min @c0 @c1))
+ (convert (min @c0 @c1)))))
+ (if (cmp == GE_EXPR || cmp == UNGE_EXPR || cmp == GT_EXPR || cmp ==
UNGT_EXPR)
+ (if (!HONOR_NANS (type))
+ (if (VECTOR_TYPE_P (type))
+ (view_convert (max @c0 @c1))
+ (convert (max @c0 @c1)))))
+ (if (cmp == UNEQ_EXPR)
+ (if (!HONOR_NANS (type))
+ (if (VECTOR_TYPE_P (type))
+ (view_convert @c1)
+ (convert @c1))))
+ (if (cmp == LTGT_EXPR)
+ (if (!HONOR_NANS (type))
+ (if (VECTOR_TYPE_P (type))
+ (view_convert @c0)
+ (convert @c0))))))))
+#endif
+
/* X != C1 ? -X : C2 simplifies to -X when -C1 == C2. */
(simplify
(cond (ne @0 INTEGER_CST@1) (negate@3 @0) INTEGER_CST@2)
--
2.35.3
