Hi.
I'm suggesting one multiplication simplification pattern.
Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
Ready to be installed?
Thanks,
Martin
gcc/ChangeLog:
2019-06-05 Martin Liska <mli...@suse.cz>
PR tree-optimization/87954
* match.pd: Simplify mult where both arguments are 0 or 1.
gcc/testsuite/ChangeLog:
2019-06-05 Martin Liska <mli...@suse.cz>
PR tree-optimization/87954
* gcc.dg/pr87954.c: New test.
---
gcc/match.pd | 8 ++++++++
gcc/testsuite/gcc.dg/pr87954.c | 21 +++++++++++++++++++++
2 files changed, 29 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/pr87954.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 02e0471dd4e..7c6bf621917 100644
--- a/gcc/match.pd
+++ b/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)
+ && wi::eq_p (get_nonzero_bits (@1), wi::one (TYPE_PRECISION (type)))
+ && wi::eq_p (get_nonzero_bits (@2), wi::one (TYPE_PRECISION (type))))
+ (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
diff --git a/gcc/testsuite/gcc.dg/pr87954.c b/gcc/testsuite/gcc.dg/pr87954.c
new file mode 100644
index 00000000000..620657cb1f5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr87954.c
@@ -0,0 +1,21 @@
+/* { 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" } } */
