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Diffstat (limited to 'libgo/go/runtime/mkpreempt.go')
| -rw-r--r-- | libgo/go/runtime/mkpreempt.go | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/libgo/go/runtime/mkpreempt.go b/libgo/go/runtime/mkpreempt.go index 64e220772e1..31b6f5cbac3 100644 --- a/libgo/go/runtime/mkpreempt.go +++ b/libgo/go/runtime/mkpreempt.go @@ -244,6 +244,15 @@ func genAMD64() { // TODO: MXCSR register? + // Apparently, the signal handling code path in darwin kernel leaves + // the upper bits of Y registers in a dirty state, which causes + // many SSE operations (128-bit and narrower) become much slower. + // Clear the upper bits to get to a clean state. See issue #37174. + // It is safe here as Go code don't use the upper bits of Y registers. + p("#ifdef GOOS_darwin") + p("VZEROUPPER") + p("#endif") + p("PUSHQ BP") p("MOVQ SP, BP") p("// Save flags before clobbering them") |