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| author | Kristina Martsenko <kristina.martsenko@arm.com> | 2016-07-28 14:29:28 +0000 |
|---|---|---|
| committer | Wilco Dijkstra <wilco@gcc.gnu.org> | 2016-07-28 14:29:28 +0000 |
| commit | dde23f43f9b80286ebed873431d7707a800f9043 (patch) | |
| tree | f82b0fcf97f2cdf5376d6c3f63001934b8c4a480 /gcc | |
| parent | 89ac681e18c3eace27e14bf03ff028bacd37e841 (diff) | |
| download | gcc-dde23f43f9b80286ebed873431d7707a800f9043.zip gcc-dde23f43f9b80286ebed873431d7707a800f9043.tar.gz gcc-dde23f43f9b80286ebed873431d7707a800f9043.tar.bz2 | |
This patchset improves zero extend costs and code generation.
When zero extending a 32-bit register, we emit a "mov", but currently
report the cost of the "mov" incorrectly.
In terms of speed, we currently say the cost is that of an extend
operation. But the cost of a "mov" is the cost of 1 instruction, so fix
that.
In terms of size, we currently say that the "mov" takes 0 instructions.
Fix it by changing it to 1.
Bootstrapped and tested on aarch64-none-elf.
gcc/
* config/aarch64/aarch64.c (aarch64_rtx_costs): Fix cost of zero extend.
From-SVN: r238820
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/config/aarch64/aarch64.c | 11 |
2 files changed, 10 insertions, 5 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 16db0ab..6945af9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2016-07-28 Kristina Martsenko <kristina.martsenko@arm.com> + + * config/aarch64/aarch64.c (aarch64_rtx_costs): Fix cost of zero extend. + 2016-07-28 Wilco Dijkstra <wdijkstr@arm.com> * config/aarch64/aarch64.c (aarch64_pushwb_pair_reg): Rename. diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index d456670..e91811d 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -6803,11 +6803,12 @@ cost_plus: { int op_cost = rtx_cost (op0, VOIDmode, ZERO_EXTEND, 0, speed); - if (!op_cost && speed) - /* MOV. */ - *cost += extra_cost->alu.extend; - else - /* Free, the cost is that of the SI mode operation. */ + /* If OP_COST is non-zero, then the cost of the zero extend + is effectively the cost of the inner operation. Otherwise + we have a MOV instruction and we take the cost from the MOV + itself. This is true independently of whether we are + optimizing for space or time. */ + if (op_cost) *cost = op_cost; return true; |