Simplify mult where both arguments are 0 or 1 (PR tree-optimization/87954).

2019-06-06  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/87954
	* match.pd: Simplify mult where both arguments are 0 or 1.
2019-06-06  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/87954
	* gcc.dg/pr87954.c: New test.

From-SVN: r271991

gcc/ChangeLog

+2019-06-06  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/87954
+	* match.pd: Simplify mult where both arguments are 0 or 1.
+
 2019-06-06  Richard Biener  <rguenther@suse.de>
 
 	* vr-values.c (vr_values::extract_range_from_ssa_name): Do not

gcc/match.pd

@@ -217,6 +217,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
            || !COMPLEX_FLOAT_TYPE_P (type)))
    (negate @0)))
 
+/* Transform { 0 or 1 } * { 0 or 1 } into { 0 or 1 } & { 0 or 1 } */
+(simplify
+ (mult SSA_NAME@1 SSA_NAME@2)
+  (if (INTEGRAL_TYPE_P (type)
+       && get_nonzero_bits (@1) == 1
+       && get_nonzero_bits (@2) == 1)
+   (bit_and @1 @2)))
+
 /* Transform x * { 0 or 1, 0 or 1, ... } into x & { 0 or -1, 0 or -1, ...},
    unless the target has native support for the former but not the latter.  */
 (simplify

gcc/testsuite/ChangeLog

+2019-06-06  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/87954
+	* gcc.dg/pr87954.c: New test.
+
 2019-06-06  Richard Biener  <rguenther@suse.de>
 
 	* gcc.dg/tree-ssa/alias-37.c: New testcase.

gcc/testsuite/gcc.dg/pr87954.c

+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#define __GFP_DMA 1u
+#define __GFP_RECLAIM 0x10u
+
+#define KMALLOC_DMA 2
+#define KMALLOC_RECLAIM 1
+
+unsigned int
+imul(unsigned int flags)
+{
+  int is_dma, type_dma, is_rec;
+
+  is_dma = !!(flags & __GFP_DMA);
+  type_dma = is_dma * KMALLOC_DMA;
+  is_rec = !!(flags & __GFP_RECLAIM);
+
+  return type_dma + (is_rec * !is_dma) * KMALLOC_RECLAIM;
+}
+
+/* { dg-final { scan-tree-dump-times { \* } 1 "optimized" } } */