| commit | 9fbb6fa123be81c55e888e5d117e63d05780f0ed | |
| author | Siddhesh Poyarekar <siddhesh@gotplt.org> | |
| Tue, 19 Oct 2021 04:06:35 +0000 (19 09:36 +0530) | ||
| committer | Siddhesh Poyarekar <siddhesh@gotplt.org> | |
| Wed, 20 Oct 2021 02:58:20 +0000 (20 08:28 +0530) | ||
| tree | 21192de96a3f53dd030f8955723ab079c615fd8c | treesnapshot (tar.gz zip) |
| parent | 3c8d8c0be95e99dc0cba7f6fad2429243582119f | commitdiff |
tree-object-size: Make unknown a computation
Compute the unknown size value as a function of the min/max bit of
object_size_type. This transforms into a neat little branchless
sequence on x86_64:
movl %edi, %eax
sarl %eax
xorl $1, %eax
negl %eax
cltq
which should be faster than loading the value from memory. A quick
unscientific test using
`time make check-gcc RUNTESTFLAGS="dg.exp=builtin*"`
shaves about half a second off execution time with this. Also simplify
implementation of unknown_object_size.
gcc/ChangeLog:
* tree-object-size.c (unknown): Make into a function. Adjust
all uses.
(unknown_object_size): Simplify implementation.
Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
Compute the unknown size value as a function of the min/max bit of
object_size_type. This transforms into a neat little branchless
sequence on x86_64:
movl %edi, %eax
sarl %eax
xorl $1, %eax
negl %eax
cltq
which should be faster than loading the value from memory. A quick
unscientific test using
`time make check-gcc RUNTESTFLAGS="dg.exp=builtin*"`
shaves about half a second off execution time with this. Also simplify
implementation of unknown_object_size.
gcc/ChangeLog:
* tree-object-size.c (unknown): Make into a function. Adjust
all uses.
(unknown_object_size): Simplify implementation.
Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
| gcc/tree-object-size.c | diffblobblamehistory |