Reviewers: Sven Panne, Rodolph Perfetta,
Message:
Hey Sven,
Here's another cleanup of useless branches in ARM full and lithium codegen.
PTAL
-- Benedikt
Description:
[arm] Drop useless branches in full and lithium codegen.
Please review this at https://codereview.chromium.org/100483006/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+16, -42 lines):
M src/arm/full-codegen-arm.cc
M src/arm/lithium-codegen-arm.cc
M src/arm/macro-assembler-arm.h
Index: src/arm/full-codegen-arm.cc
diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index
f6d3ea36ab8ce6e0ce21759ce369e8be34db2666..b0d0b8564178d602f9fb32ff11f78ca9b3c5ccfb
100644
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -2439,12 +2439,9 @@ void
FullCodeGenerator::EmitVariableAssignment(Variable* var,
// Const initializers need a write barrier.
ASSERT(!var->IsParameter()); // No const parameters.
if (var->IsStackLocal()) {
- Label skip;
__ ldr(r1, StackOperand(var));
__ CompareRoot(r1, Heap::kTheHoleValueRootIndex);
- __ b(ne, &skip);
- __ str(result_register(), StackOperand(var));
- __ bind(&skip);
+ __ str(result_register(), StackOperand(var), eq);
} else {
ASSERT(var->IsContextSlot() || var->IsLookupSlot());
// Like var declarations, const declarations are hoisted to function
@@ -3181,14 +3178,11 @@ void
FullCodeGenerator::EmitIsConstructCall(CallRuntime* expr) {
__ ldr(r2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
// Skip the arguments adaptor frame if it exists.
- Label check_frame_marker;
__ ldr(r1, MemOperand(r2, StandardFrameConstants::kContextOffset));
__ cmp(r1, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
- __ b(ne, &check_frame_marker);
- __ ldr(r2, MemOperand(r2, StandardFrameConstants::kCallerFPOffset));
+ __ ldr(r2, MemOperand(r2, StandardFrameConstants::kCallerFPOffset), eq);
// Check the marker in the calling frame.
- __ bind(&check_frame_marker);
__ ldr(r1, MemOperand(r2, StandardFrameConstants::kMarkerOffset));
__ cmp(r1, Operand(Smi::FromInt(StackFrame::CONSTRUCT)));
PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
@@ -3239,7 +3233,7 @@ void FullCodeGenerator::EmitArguments(CallRuntime*
expr) {
void FullCodeGenerator::EmitArgumentsLength(CallRuntime* expr) {
ASSERT(expr->arguments()->length() == 0);
- Label exit;
+
// Get the number of formal parameters.
__ mov(r0, Operand(Smi::FromInt(info_->scope()->num_parameters())));
@@ -3247,13 +3241,11 @@ void
FullCodeGenerator::EmitArgumentsLength(CallRuntime* expr) {
__ ldr(r2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
__ ldr(r3, MemOperand(r2, StandardFrameConstants::kContextOffset));
__ cmp(r3, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
- __ b(ne, &exit);
// Arguments adaptor case: Read the arguments length from the
// adaptor frame.
- __ ldr(r0, MemOperand(r2,
ArgumentsAdaptorFrameConstants::kLengthOffset));
+ __ ldr(r0, MemOperand(r2,
ArgumentsAdaptorFrameConstants::kLengthOffset), eq);
- __ bind(&exit);
context()->Plug(r0);
}
@@ -3378,8 +3370,7 @@ void FullCodeGenerator::EmitValueOf(CallRuntime*
expr) {
__ JumpIfSmi(r0, &done);
// If the object is not a value type, return the object.
__ CompareObjectType(r0, r1, r1, JS_VALUE_TYPE);
- __ b(ne, &done);
- __ ldr(r0, FieldMemOperand(r0, JSValue::kValueOffset));
+ __ ldr(r0, FieldMemOperand(r0, JSValue::kValueOffset), eq);
__ bind(&done);
context()->Plug(r0);
Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index
8f1c9c090dfbdf6e1de38ed34c1f028a2efbe8b0..425acdbd48c70ad6a2894e05162c13888c84af6a
100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -1414,12 +1414,9 @@ void LCodeGen::DoDivI(LDivI* instr) {
// Check for (kMinInt / -1).
if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
- Label left_not_min_int;
__ cmp(left, Operand(kMinInt));
- __ b(ne, &left_not_min_int);
- __ cmp(right, Operand(-1));
+ __ cmp(right, Operand(-1), eq);
DeoptimizeIf(eq, instr->environment());
- __ bind(&left_not_min_int);
}
if (CpuFeatures::IsSupported(SUDIV)) {
@@ -1518,12 +1515,9 @@ void LCodeGen::DoMathFloorOfDiv(LMathFloorOfDiv*
instr) {
// Check for (kMinInt / -1).
if (instr->hydrogen()->CheckFlag(HValue::kCanOverflow)) {
- Label left_not_min_int;
__ cmp(left, Operand(kMinInt));
- __ b(ne, &left_not_min_int);
- __ cmp(right, Operand(-1));
+ __ cmp(right, Operand(-1), eq);
DeoptimizeIf(eq, instr->environment());
- __ bind(&left_not_min_int);
}
// Check for (0 / -x) that will produce negative zero.
@@ -1892,8 +1886,7 @@ void LCodeGen::DoValueOf(LValueOf* instr) {
// If the object is not a value type, return the object.
__ CompareObjectType(input, map, map, JS_VALUE_TYPE);
__ Move(result, input, ne);
- __ b(ne, &done);
- __ ldr(result, FieldMemOperand(input, JSValue::kValueOffset));
+ __ ldr(result, FieldMemOperand(input, JSValue::kValueOffset), eq);
__ bind(&done);
}
@@ -3447,16 +3440,12 @@ void LCodeGen::DoArgumentsLength(LArgumentsLength*
instr) {
// If no arguments adaptor frame the number of arguments is fixed.
__ cmp(fp, elem);
__ mov(result, Operand(scope()->num_parameters()));
- __ b(eq, &done);
// Arguments adaptor frame present. Get argument length from there.
- __ ldr(result, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+ __ ldr(result, MemOperand(fp, StandardFrameConstants::kCallerFPOffset),
ne);
__ ldr(result,
- MemOperand(result,
ArgumentsAdaptorFrameConstants::kLengthOffset));
- __ SmiUntag(result);
-
- // Argument length is in result register.
- __ bind(&done);
+ MemOperand(result,
ArgumentsAdaptorFrameConstants::kLengthOffset), ne);
+ __ SmiUntag(result, LeaveCC, ne);
}
@@ -3878,16 +3867,13 @@ void LCodeGen::DoMathPowHalf(LMathPowHalf* instr) {
// Note that according to ECMA-262 15.8.2.13:
// Math.pow(-Infinity, 0.5) == Infinity
// Math.sqrt(-Infinity) == NaN
- Label done;
__ vmov(temp, -V8_INFINITY, scratch0());
__ VFPCompareAndSetFlags(input, temp);
__ vneg(result, temp, eq);
- __ b(&done, eq);
// Add +0 to convert -0 to +0.
- __ vadd(result, input, kDoubleRegZero);
- __ vsqrt(result, result);
- __ bind(&done);
+ __ vadd(result, input, kDoubleRegZero, ne);
+ __ vsqrt(result, result, ne);
}
@@ -5587,14 +5573,11 @@ void LCodeGen::EmitIsConstructCall(Register temp1,
Register temp2) {
__ ldr(temp1, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
// Skip the arguments adaptor frame if it exists.
- Label check_frame_marker;
__ ldr(temp2, MemOperand(temp1, StandardFrameConstants::kContextOffset));
__ cmp(temp2, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));
- __ b(ne, &check_frame_marker);
- __ ldr(temp1, MemOperand(temp1,
StandardFrameConstants::kCallerFPOffset));
+ __ ldr(temp1, MemOperand(temp1,
StandardFrameConstants::kCallerFPOffset), eq);
// Check the marker in the calling frame.
- __ bind(&check_frame_marker);
__ ldr(temp1, MemOperand(temp1, StandardFrameConstants::kMarkerOffset));
__ cmp(temp1, Operand(Smi::FromInt(StackFrame::CONSTRUCT)));
}
Index: src/arm/macro-assembler-arm.h
diff --git a/src/arm/macro-assembler-arm.h b/src/arm/macro-assembler-arm.h
index
f71c1a3852cfb362ba2b54a26c45143f69043308..944e6e89d7aa37b659348bdcd7bb8ec1a3ce8573
100644
--- a/src/arm/macro-assembler-arm.h
+++ b/src/arm/macro-assembler-arm.h
@@ -1257,8 +1257,8 @@ class MacroAssembler: public Assembler {
}
- void SmiUntag(Register reg, SBit s = LeaveCC) {
- mov(reg, Operand::SmiUntag(reg), s);
+ void SmiUntag(Register reg, SBit s = LeaveCC, Condition cond = al) {
+ mov(reg, Operand::SmiUntag(reg), s, cond);
}
void SmiUntag(Register dst, Register src, SBit s = LeaveCC) {
mov(dst, Operand::SmiUntag(src), s);
--
--
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