| commit | cce2ec77ff1f51275ae52d9ee365e6412f0fbb70 | |
| author | Steve Walk <Steve.Walk@cavium.com> | |
| Wed, 8 Feb 2017 20:13:42 +0000 (8 12:13 -0800) | ||
| committer | Hhvm Bot <hhvm-bot@users.noreply.github.com> | |
| Wed, 8 Feb 2017 20:32:35 +0000 (8 12:32 -0800) | ||
| tree | 8a5c9aaea0a8f2af23439f391f87a59123133eff | treesnapshot (tar.gz zip) |
| parent | 71a09ed2a935c3260c0cec312c993cf073a1ddc0 | commitdiff |
Aarch64 - loadb/movxbl -> loadzbl peephole
Summary:
On Aarch64 the loadb/movxbl sequence would generate ldrsb/uxtb.
This occurred around the Vinstr cmpbm instructions. It is equivalent to just use
the ldrb instruction and save one instruction per instance.
Before
====
14854 0: FPushFuncD 0 "ut_main"
14855 (03) EndGuards
14856 (07) t3:Func = LdFuncCached<ut_main> -> B2<Catch>
14857 Main:
14858 0x296008b0 d28217e0 movz x0, #0x10bf
14859 0x296008b4 38e06b60 ldrsb w0, [x27, x0] // <<--+
14860 0x296008b8 53001c00 uxtb w0, w0 // <<--+
14861 0x296008bc d29fffe1 movz x1, #0xffff
14862 0x296008c0 f2a05fe1 movk x1, #0x2ff, lsl #16
14863 0x296008c4 38616b61 ldrb w1, [x27, x1]
14864 0x296008c8 6b00003f cmp w1, w0
After
=====
320 0: FPushFuncD 0 "ut_main"
32
Closes https://github.com/facebook/hhvm/pull/7593
Differential Revision: D4442877
Pulled By: mxw
fbshipit-source-id: 04af9bc4ce61ece185e6fa225b1b12950f0bab58
Summary:
On Aarch64 the loadb/movxbl sequence would generate ldrsb/uxtb.
This occurred around the Vinstr cmpbm instructions. It is equivalent to just use
the ldrb instruction and save one instruction per instance.
Before
====
14854 0: FPushFuncD 0 "ut_main"
14855 (03) EndGuards
14856 (07) t3:Func = LdFuncCached<ut_main> -> B2<Catch>
14857 Main:
14858 0x296008b0 d28217e0 movz x0, #0x10bf
14859 0x296008b4 38e06b60 ldrsb w0, [x27, x0] // <<--+
14860 0x296008b8 53001c00 uxtb w0, w0 // <<--+
14861 0x296008bc d29fffe1 movz x1, #0xffff
14862 0x296008c0 f2a05fe1 movk x1, #0x2ff, lsl #16
14863 0x296008c4 38616b61 ldrb w1, [x27, x1]
14864 0x296008c8 6b00003f cmp w1, w0
After
=====
320 0: FPushFuncD 0 "ut_main"
32
Closes https://github.com/facebook/hhvm/pull/7593
Differential Revision: D4442877
Pulled By: mxw
fbshipit-source-id: 04af9bc4ce61ece185e6fa225b1b12950f0bab58
| hphp/runtime/vm/jit/vasm-simplify.cpp | diffblobblamehistory |