Hi,
Please find attached the patch that performs optimization on unsigned values.
Original fold-const part implemented in match.pd.
Please review the patch and let us know if it's OK?
Regression Tested on X86_64 with no regressions.
Thanks,
Naveen
ChangeLog:
* match.pd (cmp (convert (bit_not @0)) INTEGER_CST@1): New Simplifier.
Testsuite/ChangeLog:
* gcc.dg/pr31531.c : New testcase.
diff --git a/gcc/match.pd b/gcc/match.pd
index 6c8ebd5..42f772b 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1452,6 +1452,17 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
&& (TYPE_SIZE (TREE_TYPE (@0)) == TYPE_SIZE (TREE_TYPE (@1))))
(view_convert @1)))
+/* Fold ((CAST)~X) op C as ((CAST)X) op' ~C, where op' is the
+ swapped comparison. */
+(for cmp (tcc_comparison)
+ scmp (swapped_tcc_comparison)
+ (simplify
+ (cmp (convert (bit_not @0)) INTEGER_CST@1)
+ (if (TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (@0))
+ && TYPE_PRECISION (TREE_TYPE (@0)) == TYPE_PRECISION (TREE_TYPE (@1)))
+ (with { tree cst = fold_convert (TREE_TYPE (@0), @1); }
+ (scmp @0 (bit_not { cst; }))))))
+
/* Re-association barriers around constants and other re-association
barriers can be removed. */
(simplify
diff --git a/gcc/testsuite/gcc.dg/pr31531.c b/gcc/testsuite/gcc.dg/pr31531.c
new file mode 100644
index 0000000..d687c91
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr31531.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-fdump-tree-gimple" } */
+int isnegative_optimized_4 (unsigned int X)
+{
+ int result;
+ if ((~X) >> 31)
+ result = 0;
+ else
+ result = 1;
+ return result;
+}
+/* { dg-final { scan-tree-dump-times "0 != 0" 1 "gimple" } } */