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| author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2018-08-22 17:31:57 +0200 |
|---|---|---|
| committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2018-08-24 08:18:56 +0200 |
| commit | 1d78043467a769ccf2d81d55f898fb37f158b14f (patch) | |
| tree | e26ffeac2e858644f02a87f558f2ccff56e1ed78 | |
| parent | 3f2cbce78f78cbae35a02eb318a86f78556f71aa (diff) | |
| download | sparse-dev-1d78043467a769ccf2d81d55f898fb37f158b14f.tar.gz | |
simplify TRUNC(SHIFT(a | b, S), N)
The simplification 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 allows 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@gmail.com>
| -rw-r--r-- | simplify.c | 6 | ||||
| -rw-r--r-- | validation/optim/and-or-bfs.c | 1 | ||||
| -rw-r--r-- | validation/optim/bitfield-store-loads.c | 1 |
3 files changed, 6 insertions, 2 deletions
@@ -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 e08b816e..f3f33204 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 99a0a03a..dc625131 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\\. |