The simplification of ((x << S) >> S) was already added
but its dual was forgotten.
Add it now.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
simplify.c | 7 +++++++
validation/optim/shl-lsr0.c | 1 -
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/simplify.c b/simplify.c
index b1ccc510d..de115d6df 100644
--- a/simplify.c
+++ b/simplify.c
@@ -683,6 +683,13 @@ static int simplify_shift(struct instruction *insn, pseudo_t pseudo, long long v
if (value >= size)
goto zero;
switch(DEF_OPCODE(def, pseudo)) {
+ case OP_LSR:
+ // replace ((x >> S) << S)
+ // by (x & (-1 << S))
+ if (def->src2 != insn->src2)
+ break;
+ mask = bits_mask(insn->size - value) << value;
+ goto replace_mask;
case OP_SHL:
case_shift_shift: // also for LSR - LSR
if (def == insn) // cyclic DAG!
diff --git a/validation/optim/shl-lsr0.c b/validation/optim/shl-lsr0.c
index 851f62842..fc2561bd1 100644
--- a/validation/optim/shl-lsr0.c
+++ b/validation/optim/shl-lsr0.c
@@ -6,7 +6,6 @@ unsigned mask(unsigned x)
/*
* check-name: shl-lsr0
* check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
*
* check-output-ignore
* check-output-contains: and\\..*0xffff8000
--
2.18.0
