Reviewers: baptiste.afsa1, jbramley, ulan,
Description:
A64: Optimize LCodeGen::DoMathFloorOfDiv after r18780
BUG=314606
[email protected],[email protected],[email protected]
Please review this at https://codereview.chromium.org/140413005/
SVN Base: https://v8.googlecode.com/svn/branches/experimental/a64
Affected files (+15, -13 lines):
M src/a64/lithium-codegen-a64.cc
Index: src/a64/lithium-codegen-a64.cc
diff --git a/src/a64/lithium-codegen-a64.cc b/src/a64/lithium-codegen-a64.cc
index
7ab8cb71cdc7223b82dfbb74b4eb97b122b1450f..d30acde190e7c9bb48c6ad8381617cacac1e917b
100644
--- a/src/a64/lithium-codegen-a64.cc
+++ b/src/a64/lithium-codegen-a64.cc
@@ -3590,18 +3590,23 @@ void LCodeGen::DoMathFloor(LMathFloor* instr) {
void LCodeGen::DoMathFloorOfDiv(LMathFloorOfDiv* instr) {
- const Register result = ToRegister32(instr->result());
- const Register left = ToRegister32(instr->left());
- const Register right = ToRegister32(instr->right());
- const Register remainder = ToRegister32(instr->temp());
+ Register result = ToRegister32(instr->result());
+ Register left = ToRegister32(instr->left());
+ Register right = ToRegister32(instr->right());
+ Register remainder = ToRegister32(instr->temp());
+
+ // This can't cause an exception on ARM, so we can speculatively
+ // execute it already now.
+ __ Sdiv(result, left, right);
// Check for x / 0.
DeoptimizeIfZero(right, instr->environment());
// Check for (kMinInt / -1).
if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
- __ Cmp(left, kMinInt);
- __ Ccmp(right, -1, ZFlag, eq);
+ // The V flag will be set iff left == kMinInt.
+ __ Cmp(left, 1);
+ __ Ccmp(right, -1, ZFlag, vs);
DeoptimizeIf(eq, instr->environment());
}
@@ -3616,17 +3621,14 @@ void LCodeGen::DoMathFloorOfDiv(LMathFloorOfDiv*
instr) {
}
Label done;
- __ Sdiv(result, left, right);
// If both operands have the same sign then we are done.
- __ Eor(remainder, left, Operand(right));
+ __ Eor(remainder, left, right);
__ Tbz(remainder, kWSignBit, &done);
// Check if the result needs to be corrected.
- __ Mul(remainder, result, right);
- __ Sub(remainder, remainder, left);
- __ Cmp(remainder, 0);
- __ B(eq, &done);
- __ Sub(result, result, Operand(1));
+ __ Msub(remainder, result, right, left);
+ __ Cbz(remainder, &done);
+ __ Sub(result, result, 1);
__ Bind(&done);
}
--
--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
---
You received this message because you are subscribed to the Google Groups "v8-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/groups/opt_out.
