Title: [286378] trunk/Source/_javascript_Core
- Revision
- 286378
- Author
- [email protected]
- Date
- 2021-12-01 12:32:39 -0800 (Wed, 01 Dec 2021)
Log Message
Disable madd4 instruction generation globally for MIPS
https://bugs.webkit.org/show_bug.cgi?id=233713
Patch by Mikhail R. Gadelha <[email protected]> on 2021-12-01
Reviewed by Yusuke Suzuki.
This is an improved version of r285788 and follows the approach used
in r231301. This patch removes the volatile attribute from the double
variable and adds a -mno-madd4 flag globally when compiling on MIPS.
* CMakeLists.txt:
* runtime/ParseInt.h:
(JSC::parseInt):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/CMakeLists.txt (286377 => 286378)
--- trunk/Source/_javascript_Core/CMakeLists.txt 2021-12-01 20:29:49 UTC (rev 286377)
+++ trunk/Source/_javascript_Core/CMakeLists.txt 2021-12-01 20:32:39 UTC (rev 286378)
@@ -1458,6 +1458,12 @@
# Avoid using fused multiply-add instructions since this could give different results
# for e.g. parseInt depending on the platform and compilation flags.
WEBKIT_ADD_TARGET_CXX_FLAGS(_javascript_Core -ffp-contract=off -fno-slp-vectorize)
+
+ # On MIPS we have to explicitly disable madd4, since some versions of gcc still generate
+ # such instructions despite -ffp-contract=off
+ if (WTF_CPU_MIPS)
+ WEBKIT_ADD_TARGET_CXX_FLAGS(_javascript_Core -mno-madd4)
+ endif ()
endif ()
WEBKIT_COPY_FILES(_javascript_Core_CopyHeaders
Modified: trunk/Source/_javascript_Core/ChangeLog (286377 => 286378)
--- trunk/Source/_javascript_Core/ChangeLog 2021-12-01 20:29:49 UTC (rev 286377)
+++ trunk/Source/_javascript_Core/ChangeLog 2021-12-01 20:32:39 UTC (rev 286378)
@@ -1,3 +1,18 @@
+2021-12-01 Mikhail R. Gadelha <[email protected]>
+
+ Disable madd4 instruction generation globally for MIPS
+ https://bugs.webkit.org/show_bug.cgi?id=233713
+
+ Reviewed by Yusuke Suzuki.
+
+ This is an improved version of r285788 and follows the approach used
+ in r231301. This patch removes the volatile attribute from the double
+ variable and adds a -mno-madd4 flag globally when compiling on MIPS.
+
+ * CMakeLists.txt:
+ * runtime/ParseInt.h:
+ (JSC::parseInt):
+
2021-12-01 Yusuke Suzuki <[email protected]>
Unreviewed, fix CLoop build
Modified: trunk/Source/_javascript_Core/runtime/ParseInt.h (286377 => 286378)
--- trunk/Source/_javascript_Core/runtime/ParseInt.h 2021-12-01 20:29:49 UTC (rev 286377)
+++ trunk/Source/_javascript_Core/runtime/ParseInt.h 2021-12-01 20:32:39 UTC (rev 286378)
@@ -162,15 +162,7 @@
// 14. Let number be the Number value for mathInt.
int firstDigitPosition = p;
bool sawDigit = false;
-#if COMPILER(GCC)
- // Due to a bug found in GCC v8.4.0, a wrong fused multiply-add optimization can be inserted when calculating the final number,
- // in number *= radix; number += digit;, so add volatile to prevent optimizations.
- // GCC v8.4.0 also seems to ignore #pragma STDC FP_CONTRACT OFF, compiling with -ffp-contract=off, and setting function attributes
- // __attribute__((optimize("fp-contract=off"))) and __attribute__((optimize("-ffp-contract=off"))).
- volatile double number = 0;
-#else
double number = 0;
-#endif
while (p < length) {
int digit = parseDigit(data[p], radix);
if (digit == -1)
_______________________________________________
webkit-changes mailing list
[email protected]
https://lists.webkit.org/mailman/listinfo/webkit-changes
