Changeset 94622 in webkit for trunk/Source/JavaScriptCore/assembler/MacroAssemblerARM.h

Timestamp:

Sep 6, 2011, 7:00:16 PM (14 years ago)

Author:

[email protected]

Message:

Source/JavaScriptCore: ​https://bugs.webkit.org/show_bug.cgi?id=67486
This reverts r65993 which gives wrong results for rshift
in some corner cases (see the test).

Patch by Yong Li <​[email protected]> on 2011-09-06
Reviewed by Gavin Barraclough.

New test: fast/js/floating-point-truncate-rshift.html

• assembler/ARMAssembler.h:
• assembler/MacroAssemblerARM.h:

(JSC::MacroAssemblerARM::supportsFloatingPointTruncate):
(JSC::MacroAssemblerARM::branchTruncateDoubleToInt32):

LayoutTests: ​https://bugs.webkit.org/show_bug.cgi?id=67486
Add a test case for branchTruncateDoubleToInt32() which is
used in right shift optimization when the assembler
"supportsFloatingPointTruncate".

Patch by Yong Li <​[email protected]> on 2011-09-06
Reviewed by Gavin Barraclough.

• fast/js/floating-point-truncate-rshift-expected.txt: Added.
• fast/js/floating-point-truncate-rshift.html: Added.

File:

• trunk/Source/JavaScriptCore/assembler/MacroAssemblerARM.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/assembler/MacroAssemblerARM.h

@@ -788 +788 @@
     bool supportsFloatingPointTruncate() const
     {
-        return s_isVFPPresent;
+        return false;
     }
 
@@ -903 +903 @@
     // If the result is not representable as a 32 bit value, branch.
     // May also branch for some values that are representable in 32 bits
-    // (specifically, in this case, INT_MIN and INT_MAX).
+    // (specifically, in this case, INT_MIN).
     Jump branchTruncateDoubleToInt32(FPRegisterID src, RegisterID dest)
     {
-        m_assembler.vcvtr_s32_f64_r(ARMRegisters::SD0 << 1, src);
-        // If VCVTR.S32.F64 can't fit the result into a 32-bit
-        // integer, it saturates at INT_MAX or INT_MIN. Testing this is
-        // probably quicker than testing FPSCR for exception.
-        m_assembler.vmov_arm_r(dest, ARMRegisters::SD0 << 1);
-        m_assembler.sub_r(ARMRegisters::S0, dest, ARMAssembler::getOp2(0x80000000));
-        m_assembler.cmn_r(ARMRegisters::S0, ARMAssembler::getOp2(1), ARMCondition(NotEqual));
-        return Jump(m_assembler.jmp(ARMCondition(Equal)));
+        UNUSED_PARAM(src);
+        UNUSED_PARAM(dest);
+        ASSERT_NOT_REACHED();
+        return jump();
     }