Could round rather than truncate in compileClampDoubleToByte?

[kmiller68]

c55d067

Could round rather than truncate in compileClampDoubleToByte?
https://bugs.webkit.org/show_bug.cgi?id=72054
rdar://113734964

Reviewed by Yusuke Suzuki.

Right now there's a difference between our non-optimizing code and our C++ code for ClampedUint8Arrays.
In the C++ code we correctly do a round to nearest (ties to even) but in the optimizing JITs we do a round to inifinity.
This patch fixes our optimizing code to round to nearest too.

* Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::clampDoubleToByte):
(JSC::DFG::compileClampDoubleToByte):
* Source/JavaScriptCore/ftl/FTLLowerDFGToB3.cpp:
(JSC::FTL::DFG::LowerDFGToB3::compileCompareStrictEq):

Canonical link: https://commits.webkit.org/267100@main

ee94e3c

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	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim		❌ 🧪 jsc-armv7-tests
✅ 🛠 🧪 merge	✅ 🛠 watch		❌ 🛠 jsc-mips
	✅ 🛠 watch-sim		❌ 🧪 jsc-mips-tests

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 88ed1fc)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	✅ 🛠 gtk
	🧪 ios-wk2-wpt	🧪 mac-wk1	🧪 gtk-wk2
✅ 🛠 🧪 jsc	🧪 api-ios	🧪 mac-wk2	🧪 api-gtk
✅ 🛠 🧪 jsc-arm64	🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🛠 jsc-armv7
	⏳ 🛠 tv-sim		✅ 🧪 jsc-armv7-tests
	⏳ 🛠 watch		❌ 🛠 jsc-mips
	✅ 🛠 watch-sim		❌ 🧪 jsc-mips-tests

[Constellation]

r=me

[webkit-early-warning-system]

EWS run on current version of this PR (hash ee94e3c)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim		❌ 🧪 jsc-armv7-tests
✅ 🛠 🧪 merge	✅ 🛠 watch		❌ 🛠 jsc-mips
	✅ 🛠 watch-sim		❌ 🧪 jsc-mips-tests

[kmiller68]

Merging despite the build/test failures for mips and armv7 per request of @jjgriego

[webkit-commit-queue]

Committed 267100@main (c55d067): https://commits.webkit.org/267100@main

Reviewed commits have been landed. Closing PR #16609 and removing active labels.