The following patch adds missing patterns with swapped comparison
operands for the @0 < @1 and @0 < @2 to @0 < min (@1, @2) transform.
This nullifies the difference gimplify-into-SSA made on
rhfuhf.F:ROFOCK which causes the function no longer to be miscompiled
(by vectorization eventually, -fno-tree-vectorize also fixes the
miscompare at r235817).
Bootstrap and regtest running on x86_64-unknown-linux-gnu.
I didn't attempt to understand the miscompile or create an executable
testcase.
Richard.
2016-05-31 Richard Biener <rguent...@suse.de>
PR tree-optimization/71311
* match.pd (@0 < @1 and @0 < @2 to @0 < min (@1, @2)): Add
cases with swapped comparison operands.
Index: gcc/match.pd
===================================================================
--- gcc/match.pd (revision 235817)
+++ gcc/match.pd (working copy)
@@ -3179,6 +3179,23 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(bit_and (op:s @0 @1) (op:s @0 @2))
(if (INTEGRAL_TYPE_P (TREE_TYPE (@0)))
(op @0 (ext @1 @2)))))
+/* Transform (@1 < @0 and @2 < @0) to use max,
+ (@1 > @0 and @2 > @0) to use min */
+(for op (lt le gt ge)
+ ext (max max min min)
+ (simplify
+ (bit_and (op:s @1 @0) (op:s @2 @0))
+ (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)))
+ (op (ext @1 @2) @0))))
+/* Transform (@0 < @1 and @2 > @0) to use min,
+ (@0 > @1 and @2 < @0) to use max */
+(for op (lt le gt ge)
+ ops (gt ge lt le)
+ ext (min min max max)
+ (simplify
+ (bit_and:c (op:s @0 @1) (ops:s @2 @0))
+ (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)))
+ (op @0 (ext @1 @2)))))
(simplify
/* signbit(x) -> 0 if x is nonnegative. */
