Re: [PATCH] Optimize certain end of loop conditions into min/max operation

[Michael Collison <michael dot collison at linaro dot org>]

Marc,

Ah I did misunderstand you. Patch with match.pd formatting fix.

On 10/01/2015 01:05 AM, Marc Glisse wrote:
> On Thu, 1 Oct 2015, Michael Collison wrote:
>
> > ChangeLog formatting and test case fixed.
>
> Oups, sorry for the lack of precision, but I meant indenting the code 
> in match.pd, I hadn't even looked at the ChangeLog.

--
Michael Collison
Linaro Toolchain Working Group
michael.collison@linaro.org

Attachment: ChangeLog.txt
Description: Text document

diff --git a/gcc/match.pd b/gcc/match.pd
index bd5c267..caf3c82 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2311,3 +2311,13 @@ along with GCC; see the file COPYING3.  If not see
     (with { tree utype = unsigned_type_for (TREE_TYPE (@0)); }
      (convert (bit_and (op (convert:utype @0) (convert:utype @1))
 	       (convert:utype @4))))))))
+
+/* Transform (@0 < @1 and @0 < @2) to use min, 
+   (@0 > @1 and @0 > @2) to use max */
+(for op (lt le gt ge)
+     ext (min min max max)
+ (simplify
+  (bit_and (op:s @0 @1) (op:s @0 @2))
+  (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)))
+   (op @0 (ext @1 @2)))))
+
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/minmax-loopend.c b/gcc/testsuite/gcc.dg/tree-ssa/minmax-loopend.c
new file mode 100644
index 0000000..2e4300c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/minmax-loopend.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+int min_test(long a, long b, long c) {
+  int cmp1 = a < b;
+  int cmp2 = a < c;
+  return cmp1 & cmp2;
+}
+
+int max_test (long a, long b, long c) {
+  int cmp1 = a > b;
+  int cmp2 = a > c;
+  return cmp1 & cmp2;
+}
+
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 1 "optimized" } } */
-- 
1.9.1