From: Roger Sayle <ro...@nextmovesoftware.com>
2020-06-24 Roger Sayle <ro...@nextmovesoftware.com>
Segher Boessenkool <seg...@kernel.crashing.org>
* simplify-rtx.c (simplify_unary_operation_1): Simplify rotates by 0.
---
gcc/simplify-rtx.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 65008ea..3e913b5 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -3645,6 +3645,8 @@ simplify_binary_operation_1 (enum rtx_code code,
machine_mode mode,
case ROTATERT:
case ROTATE:
+ if (trueop1 == CONST0_RTX (mode))
+ return op0;
/* Canonicalize rotates by constant amount. If op1 is bitsize / 2,
prefer left rotation, if op1 is from bitsize / 2 + 1 to
bitsize - 1, use other direction of rotate with 1 .. bitsize / 2 - 1
--
1.8.3.1
