It might still be possible to detect some patterns cheaply - I'l see
what I can come up with.
Also, any successful reduction in the number of passes in the peephole
optimizer will result in a speed-up that may offset any expensive checks
(and the most expensive ones can be reserved for -O3 and
Am 19.07.20 um 23:37 schrieb Stefan Glienke:
Still kinda disappointing compared to what it could be - while this is
some simple code a modern compiler should try to eliminate conditional
jumps even with the incredibly powerful branch predictors nowadays.
clang and gcc emit this - I would guess
Am 20.07.2020 um 02:37 schrieb J. Gareth Moreton:
On 19/07/2020 22:37, Stefan Glienke wrote:
clang and gcc emit this - I would guess they detect quite some common
patterns like this.
...
cmp eax, edx
mov edx, -1
setg al
movzx eax, al
cmovl eax, edx
ret
I think I
On 19/07/2020 22:37, Stefan Glienke wrote:
clang and gcc emit this - I would guess they detect quite some common
patterns like this.
...
cmp eax, edx
mov edx, -1
setg al
movzx eax, al
cmovl eax, edx
ret
I think I can make improvements to that already! (Note the se
- Reply to message -
Subject: [fpc-devel] Producing assembly with less branches?
From: Stefan Glienke
To:
Hi,
not sure if anything significantly changed in trunk compared to 3.2 wrt
to optimized code being generated but I am quite disappointed that fpc
(checked win64 with -O3 and
Am 19.07.20 um 19:24 schrieb Stefan Glienke:
Hi,
not sure if anything significantly changed in trunk compared to 3.2 wrt
to optimized code being generated but I am quite disappointed that fpc
(checked win64 with -O3 and -O4) does not use cmovxx instructions and
alike for the most basic things
- Reply to message -
Subject: [fpc-devel] Producing assembly with less branches?
From: Stefan Glienke
To:
> Hi,
> not sure if anything significantly changed in trunk compared to 3.2 wrt
> to optimized code being generated but I am quite disappointed that fpc
> (checked wi
Hi,
not sure if anything significantly changed in trunk compared to 3.2 wrt
to optimized code being generated but I am quite disappointed that fpc
(checked win64 with -O3 and -O4) does not use cmovxx instructions and
alike for the most basic things and produces terrible code like this:
unit1
