The simplication of TRUNC(SHIFT(a | b, S), N) can be done by
combining the effective mask corresponding to TRUNC(_, N) with
the one corresponding to SHIFT(_, S).
This allow to also simplify signed bitfields. For example, code like:
struct s {
signed int :2;
signed int f:3;
};
int bfs(struct s s, int a)
{
s.f = a;
return s.f;
}
is now simplified into the minimal:
bfs:
trunc.3 %r4 <- (32) %arg2
sext.32 %r11 <- (3) %r4
ret.32 %r11
The simplification is done by calling simplify_mask_shift() with
the mask corresponding to TRUNC(_, N).
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
simplify.c | 6 ++++++
validation/optim/and-or-bfs.c | 1 -
validation/optim/bitfield-store-loads.c | 1 -
3 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/simplify.c b/simplify.c
index 78688c7c3..ae23e2a69 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1437,6 +1437,12 @@ static int simplify_cast(struct instruction *insn)
return replace_pseudo(insn, &insn->src1, def->src1);
}
break;
+ case OP_LSR:
+ case OP_SHL:
+ if (insn->opcode != OP_TRUNC)
+ break;
+ mask = bits_mask(insn->size);
+ return simplify_mask_shift(def, mask);
case OP_TRUNC:
switch (insn->opcode) {
case OP_TRUNC:
diff --git a/validation/optim/and-or-bfs.c b/validation/optim/and-or-bfs.c
index e08b816e2..f3f332047 100644
--- a/validation/optim/and-or-bfs.c
+++ b/validation/optim/and-or-bfs.c
@@ -12,7 +12,6 @@ int bfs(struct s s, int a)
/*
* check-name: and-or-bfs
* check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
*
* check-output-ignore
* check-output-pattern(1): trunc\\.
diff --git a/validation/optim/bitfield-store-loads.c b/validation/optim/bitfield-store-loads.c
index 99a0a03a7..dc625131e 100644
--- a/validation/optim/bitfield-store-loads.c
+++ b/validation/optim/bitfield-store-loads.c
@@ -12,7 +12,6 @@ int foo(struct s s, int a)
/*
* check-name: bitfield-store-load signed
* check-command: test-linearize -Wno-decl $file
- * check-known-to-fail
*
* check-output-ignore
* check-output-excludes: shl\\.
--
2.18.0
