[webkit-changes] [150992] trunk/Source/JavaScriptCore

Thu, 30 May 2013 16:20:08 -0700

Title: [150992] trunk/Source/_javascript_Core
Revision
150992
Author
[email protected]
Date
2013-05-30 16:21:17 -0700 (Thu, 30 May 2013)

Log Message

[sh4] Optimize NaN checks in LLINT for floating point comparisons.
https://bugs.webkit.org/show_bug.cgi?id=117049

Patch by Julien Brianceau <[email protected]> on 2013-05-30
Reviewed by Oliver Hunt.

Use the fcmp/eq opcode in sh4 LLINT to test if a double is NaN.
This is more efficient, doesn't require two tmp registers and requires
less code than current implementation (which converts double to float,
then checks 'E = Emax + 1' and 'f != 0').

* offlineasm/sh4.rb:

Modified Paths

Diff

Modified: trunk/Source/_javascript_Core/ChangeLog (150991 => 150992)


--- trunk/Source/_javascript_Core/ChangeLog	2013-05-30 23:15:36 UTC (rev 150991)
+++ trunk/Source/_javascript_Core/ChangeLog	2013-05-30 23:21:17 UTC (rev 150992)
@@ -1,3 +1,17 @@
+2013-05-30  Julien Brianceau  <[email protected]>
+
+        [sh4] Optimize NaN checks in LLINT for floating point comparisons.
+        https://bugs.webkit.org/show_bug.cgi?id=117049
+
+        Reviewed by Oliver Hunt.
+
+        Use the fcmp/eq opcode in sh4 LLINT to test if a double is NaN.
+        This is more efficient, doesn't require two tmp registers and requires
+        less code than current implementation (which converts double to float,
+        then checks 'E = Emax + 1' and 'f != 0').
+
+        * offlineasm/sh4.rb:
+
 2013-05-30  Oliver Hunt  <[email protected]>
 
         JSCallbackObject does not correctly initialise the PropertySlot for getOwnPropertyDescriptor

Modified: trunk/Source/_javascript_Core/offlineasm/sh4.rb (150991 => 150992)


--- trunk/Source/_javascript_Core/offlineasm/sh4.rb	2013-05-30 23:15:36 UTC (rev 150991)
+++ trunk/Source/_javascript_Core/offlineasm/sh4.rb	2013-05-30 23:21:17 UTC (rev 150992)
@@ -320,21 +320,17 @@
             case node.opcode
             when "bdltun", "bdgtun"
                 # Handle specific floating point unordered opcodes.
-                tmp1 = Tmp.new(codeOrigin, :gpr)
-                tmp2 = Tmp.new(codeOrigin, :gpr)
-                newList << Instruction.new(codeOrigin, "bdnan", [node.operands[0], node.operands[2], tmp1, tmp2])
-                newList << Instruction.new(codeOrigin, "bdnan", [node.operands[1], node.operands[2], tmp1, tmp2])
+                newList << Instruction.new(codeOrigin, "bdnan", [node.operands[0], node.operands[2]])
+                newList << Instruction.new(codeOrigin, "bdnan", [node.operands[1], node.operands[2]])
                 newList << Instruction.new(codeOrigin, node.opcode[0..-3], node.operands)
             when "bdnequn", "bdgtequn", "bdltequn"
                 newList << Instruction.new(codeOrigin, node.opcode[0..-3], node.operands)
             when "bdneq", "bdgteq", "bdlteq"
                 # Handle specific floating point ordered opcodes.
-                tmp1 = Tmp.new(codeOrigin, :gpr)
-                tmp2 = Tmp.new(codeOrigin, :gpr)
                 outlabel = LocalLabel.unique("out_#{node.opcode}")
                 outref = LocalLabelReference.new(codeOrigin, outlabel)
-                newList << Instruction.new(codeOrigin, "bdnan", [node.operands[0], outref, tmp1, tmp2])
-                newList << Instruction.new(codeOrigin, "bdnan", [node.operands[1], outref, tmp1, tmp2])
+                newList << Instruction.new(codeOrigin, "bdnan", [node.operands[0], outref])
+                newList << Instruction.new(codeOrigin, "bdnan", [node.operands[1], outref])
                 newList << Instruction.new(codeOrigin, node.opcode, node.operands)
                 newList << outlabel
             else
@@ -544,40 +540,9 @@
 end
 
 def emitSH4BranchIfNaN(operands)
-    raise "Invalid operands number (#{operands.size})" unless operands.size == 4
-    dblop = operands[0]
-    labelop = operands[1]
-    scrmask = operands[2]
-    scrint = operands[3]
-
-    notNaNlabel = LocalLabel.unique("notnan")
-    notNaNref = LocalLabelReference.new(codeOrigin, notNaNlabel)
-    constlabel1 = LocalLabel.unique("notnanConst1")
-    constlabel2 = LocalLabel.unique("notnanConst2")
-
-    # If we don't have "E = Emax + 1", it's not a NaN.
-    $asm.puts "fcnvds #{dblop.sh4Operand}, fpul"
-    $asm.puts "sts fpul, #{scrint.sh4Operand}"
-    $asm.puts "mov.l #{LocalLabelReference.new(codeOrigin, constlabel1).asmLabel}, #{scrmask.sh4Operand}"
-    $asm.puts "and #{sh4Operands([scrmask, scrint])}"
-    $asm.puts "cmp/eq #{sh4Operands([scrmask, scrint])}"
-    $asm.puts "bf #{notNaNref.asmLabel}"
-
-    # If we have "E = Emax + 1" and "f != 0", then it's a NaN.
-    $asm.puts "sts fpul, #{scrint.sh4Operand}"
-    $asm.puts "mov.l #{LocalLabelReference.new(codeOrigin, constlabel2).asmLabel}, #{scrmask.sh4Operand}"
-    $asm.puts "tst #{sh4Operands([scrmask, scrint])}"
-    $asm.puts "bt #{notNaNref.asmLabel}"
-    $asm.puts "bra #{labelop.asmLabel}"
-    $asm.puts "nop"
-
-    $asm.puts ".balign 4"
-    constlabel1.lower("SH4")
-    $asm.puts ".long 0x7f800000"
-    constlabel2.lower("SH4")
-    $asm.puts ".long 0x003fffff"
-
-    notNaNlabel.lower("SH4")
+    raise "Invalid operands number (#{operands.size})" unless operands.size == 2
+    $asm.puts "fcmp/eq #{sh4Operands([operands[0], operands[0]])}"
+    $asm.puts "bf #{operands[1].asmLabel}"
 end
 
 def emitSH4DoubleCondBranch(cmpOpcode, neg, operands)

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