Hello,
this simple transformation is currently done in RTL, sometimes also
in VRP if we have any kind of range information (even on the wrong side,
but not with VR_VARYING). It seems more natural to complete the match.pd
pattern than make VRP understand this case.
Bootstrap+regtest on powerpc64le-unknown-linux-gnu (some noise in libgomp
testcases).
2016-04-21 Marc Glisse <marc.gli...@inria.fr>
gcc/
* match.pd (min(int_max, x), max(int_min, x)): New transformations.
gcc/testsuite/
* gcc.dg/tree-ssa/minmax-1.c: New testcase.
--
Marc GlisseIndex: gcc/match.pd
===================================================================
--- gcc/match.pd (revision 235292)
+++ gcc/match.pd (working copy)
@@ -1185,30 +1185,40 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* min(max(x,y),y) -> y. */
(simplify
(min:c (max:c @0 @1) @1)
@1)
/* max(min(x,y),y) -> y. */
(simplify
(max:c (min:c @0 @1) @1)
@1)
(simplify
(min @0 @1)
- (if (INTEGRAL_TYPE_P (type)
- && TYPE_MIN_VALUE (type)
- && operand_equal_p (@1, TYPE_MIN_VALUE (type), OEP_ONLY_CONST))
- @1))
+ (switch
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_MIN_VALUE (type)
+ && operand_equal_p (@1, TYPE_MIN_VALUE (type), OEP_ONLY_CONST))
+ @1)
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_MAX_VALUE (type)
+ && operand_equal_p (@1, TYPE_MAX_VALUE (type), OEP_ONLY_CONST))
+ @0)))
(simplify
(max @0 @1)
- (if (INTEGRAL_TYPE_P (type)
- && TYPE_MAX_VALUE (type)
- && operand_equal_p (@1, TYPE_MAX_VALUE (type), OEP_ONLY_CONST))
- @1))
+ (switch
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_MAX_VALUE (type)
+ && operand_equal_p (@1, TYPE_MAX_VALUE (type), OEP_ONLY_CONST))
+ @1)
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_MIN_VALUE (type)
+ && operand_equal_p (@1, TYPE_MIN_VALUE (type), OEP_ONLY_CONST))
+ @0)))
(for minmax (FMIN FMAX)
/* If either argument is NaN, return the other one. Avoid the
transformation if we get (and honor) a signalling NaN. */
(simplify
(minmax:c @0 REAL_CST@1)
(if (real_isnan (TREE_REAL_CST_PTR (@1))
&& (!HONOR_SNANS (@1) || !TREE_REAL_CST (@1).signalling))
@0)))
/* Convert fmin/fmax to MIN_EXPR/MAX_EXPR. C99 requires these
functions to return the numeric arg if the other one is NaN.
Index: gcc/testsuite/gcc.dg/tree-ssa/minmax-1.c
===================================================================
--- gcc/testsuite/gcc.dg/tree-ssa/minmax-1.c (revision 0)
+++ gcc/testsuite/gcc.dg/tree-ssa/minmax-1.c (working copy)
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-optimized" } */
+
+static int min(int a,int b){return (a<b)?a:b;}
+static int max(int a,int b){return (a<b)?b:a;}
+int f(int x){return max(x,-__INT_MAX__-1);}
+int g(int x){return min(x,__INT_MAX__);}
+
+/* { dg-final { scan-tree-dump-times "return x_\[0-9\]+.D.;" 2 "optimized" } }
*/
