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Unified Diff: src/mips/macro-assembler-mips.cc

Issue 1434263003: MIPS: Use BOVC/BNVC for overflow checking on r6. (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Remove unnecessary BranchOnOverflow() call. Created 5 years ago
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Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index 8eb26256d308dde7cf9b3d5fbb8ed9b69a141a5e..ff45b3f3025799141f178ea2b06e0b4f1c4de5b4 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -4295,108 +4295,161 @@ void MacroAssembler::SmiToDoubleFPURegister(Register smi,
}
-void MacroAssembler::AdduAndCheckForOverflow(Register dst, Register left,
- const Operand& right,
- Register overflow_dst,
- Register scratch) {
+static inline void BranchOvfHelper(MacroAssembler* masm, Register overflow_dst,
+ Label* overflow_label,
+ Label* no_overflow_label) {
+ DCHECK(overflow_label || no_overflow_label);
+ if (!overflow_label) {
+ DCHECK(no_overflow_label);
+ masm->Branch(no_overflow_label, ge, overflow_dst, Operand(zero_reg));
+ } else {
+ masm->Branch(overflow_label, lt, overflow_dst, Operand(zero_reg));
+ if (no_overflow_label) masm->Branch(no_overflow_label);
+ }
+}
+
+
+void MacroAssembler::AddBranchOvf(Register dst, Register left,
+ const Operand& right, Label* overflow_label,
+ Label* no_overflow_label, Register scratch) {
if (right.is_reg()) {
- AdduAndCheckForOverflow(dst, left, right.rm(), overflow_dst, scratch);
+ AddBranchOvf(dst, left, right.rm(), overflow_label, no_overflow_label,
+ scratch);
} else {
- if (dst.is(left)) {
- mov(scratch, left); // Preserve left.
- Addu(dst, left, right.immediate()); // Left is overwritten.
- xor_(scratch, dst, scratch); // Original left.
- // Load right since xori takes uint16 as immediate.
- Addu(t9, zero_reg, right);
- xor_(overflow_dst, dst, t9);
- and_(overflow_dst, overflow_dst, scratch);
+ if (IsMipsArchVariant(kMips32r6)) {
+ Register right_reg = t9;
+ DCHECK(!left.is(right_reg));
+ li(right_reg, Operand(right));
+ AddBranchOvf(dst, left, right_reg, overflow_label, no_overflow_label);
} else {
- Addu(dst, left, right.immediate());
- xor_(overflow_dst, dst, left);
- // Load right since xori takes uint16 as immediate.
- Addu(t9, zero_reg, right);
- xor_(scratch, dst, t9);
- and_(overflow_dst, scratch, overflow_dst);
+ Register overflow_dst = t9;
+ DCHECK(!dst.is(scratch));
+ DCHECK(!dst.is(overflow_dst));
+ DCHECK(!scratch.is(overflow_dst));
+ DCHECK(!left.is(overflow_dst));
+ if (dst.is(left)) {
+ mov(scratch, left); // Preserve left.
+ Addu(dst, left, right.immediate()); // Left is overwritten.
+ xor_(scratch, dst, scratch); // Original left.
+ // Load right since xori takes uint16 as immediate.
+ Addu(overflow_dst, zero_reg, right);
+ xor_(overflow_dst, dst, overflow_dst);
+ and_(overflow_dst, overflow_dst, scratch);
+ } else {
+ Addu(dst, left, right.immediate());
+ xor_(overflow_dst, dst, left);
+ // Load right since xori takes uint16 as immediate.
+ Addu(scratch, zero_reg, right);
+ xor_(scratch, dst, scratch);
+ and_(overflow_dst, scratch, overflow_dst);
+ }
+ BranchOvfHelper(this, overflow_dst, overflow_label, no_overflow_label);
}
}
}
-void MacroAssembler::AdduAndCheckForOverflow(Register dst, Register left,
- Register right,
- Register overflow_dst,
- Register scratch) {
- DCHECK(!dst.is(overflow_dst));
- DCHECK(!dst.is(scratch));
- DCHECK(!overflow_dst.is(scratch));
- DCHECK(!overflow_dst.is(left));
- DCHECK(!overflow_dst.is(right));
-
- if (left.is(right) && dst.is(left)) {
- DCHECK(!dst.is(t9));
- DCHECK(!scratch.is(t9));
- DCHECK(!left.is(t9));
- DCHECK(!right.is(t9));
- DCHECK(!overflow_dst.is(t9));
- mov(t9, right);
- right = t9;
- }
-
- if (dst.is(left)) {
- mov(scratch, left); // Preserve left.
- addu(dst, left, right); // Left is overwritten.
- xor_(scratch, dst, scratch); // Original left.
- xor_(overflow_dst, dst, right);
- and_(overflow_dst, overflow_dst, scratch);
- } else if (dst.is(right)) {
- mov(scratch, right); // Preserve right.
- addu(dst, left, right); // Right is overwritten.
- xor_(scratch, dst, scratch); // Original right.
- xor_(overflow_dst, dst, left);
- and_(overflow_dst, overflow_dst, scratch);
+void MacroAssembler::AddBranchOvf(Register dst, Register left, Register right,
+ Label* overflow_label,
+ Label* no_overflow_label, Register scratch) {
+ if (IsMipsArchVariant(kMips32r6)) {
+ if (!overflow_label) {
+ DCHECK(no_overflow_label);
+ DCHECK(!dst.is(scratch));
+ Register left_reg = left.is(dst) ? scratch : left;
+ Register right_reg = right.is(dst) ? t9 : right;
+ DCHECK(!dst.is(left_reg));
+ DCHECK(!dst.is(right_reg));
+ Move(left_reg, left);
+ Move(right_reg, right);
+ addu(dst, left, right);
+ bnvc(left_reg, right_reg, no_overflow_label);
+ } else {
+ bovc(left, right, overflow_label);
+ addu(dst, left, right);
+ if (no_overflow_label) bc(no_overflow_label);
+ }
} else {
- addu(dst, left, right);
- xor_(overflow_dst, dst, left);
- xor_(scratch, dst, right);
- and_(overflow_dst, scratch, overflow_dst);
+ Register overflow_dst = t9;
+ DCHECK(!dst.is(scratch));
+ DCHECK(!dst.is(overflow_dst));
+ DCHECK(!scratch.is(overflow_dst));
+ DCHECK(!left.is(overflow_dst));
+ DCHECK(!right.is(overflow_dst));
+ DCHECK(!left.is(scratch));
+ DCHECK(!right.is(scratch));
+
+ if (left.is(right) && dst.is(left)) {
+ mov(overflow_dst, right);
+ right = overflow_dst;
+ }
+
+ if (dst.is(left)) {
+ mov(scratch, left); // Preserve left.
+ addu(dst, left, right); // Left is overwritten.
+ xor_(scratch, dst, scratch); // Original left.
+ xor_(overflow_dst, dst, right);
+ and_(overflow_dst, overflow_dst, scratch);
+ } else if (dst.is(right)) {
+ mov(scratch, right); // Preserve right.
+ addu(dst, left, right); // Right is overwritten.
+ xor_(scratch, dst, scratch); // Original right.
+ xor_(overflow_dst, dst, left);
+ and_(overflow_dst, overflow_dst, scratch);
+ } else {
+ addu(dst, left, right);
+ xor_(overflow_dst, dst, left);
+ xor_(scratch, dst, right);
+ and_(overflow_dst, scratch, overflow_dst);
+ }
+ BranchOvfHelper(this, overflow_dst, overflow_label, no_overflow_label);
}
}
-void MacroAssembler::SubuAndCheckForOverflow(Register dst, Register left,
- const Operand& right,
- Register overflow_dst,
- Register scratch) {
+void MacroAssembler::SubBranchOvf(Register dst, Register left,
+ const Operand& right, Label* overflow_label,
+ Label* no_overflow_label, Register scratch) {
+ DCHECK(overflow_label || no_overflow_label);
if (right.is_reg()) {
- SubuAndCheckForOverflow(dst, left, right.rm(), overflow_dst, scratch);
+ SubBranchOvf(dst, left, right.rm(), overflow_label, no_overflow_label,
+ scratch);
} else {
+ Register overflow_dst = t9;
+ DCHECK(!dst.is(scratch));
+ DCHECK(!dst.is(overflow_dst));
+ DCHECK(!scratch.is(overflow_dst));
+ DCHECK(!left.is(overflow_dst));
+ DCHECK(!left.is(scratch));
if (dst.is(left)) {
mov(scratch, left); // Preserve left.
- Subu(dst, left, right); // Left is overwritten.
- xor_(overflow_dst, dst, scratch); // scratch is original left.
+ Subu(dst, left, right.immediate()); // Left is overwritten.
// Load right since xori takes uint16 as immediate.
- Addu(t9, zero_reg, right);
- xor_(scratch, scratch, t9); // scratch is original left.
+ Addu(overflow_dst, zero_reg, right);
+ xor_(overflow_dst, scratch, overflow_dst); // scratch is original left.
+ xor_(scratch, dst, scratch); // scratch is original left.
and_(overflow_dst, scratch, overflow_dst);
} else {
Subu(dst, left, right);
xor_(overflow_dst, dst, left);
// Load right since xori takes uint16 as immediate.
- Addu(t9, zero_reg, right);
- xor_(scratch, left, t9);
+ Addu(scratch, zero_reg, right);
+ xor_(scratch, left, scratch);
and_(overflow_dst, scratch, overflow_dst);
}
+ BranchOvfHelper(this, overflow_dst, overflow_label, no_overflow_label);
}
}
-void MacroAssembler::SubuAndCheckForOverflow(Register dst, Register left,
- Register right,
- Register overflow_dst,
- Register scratch) {
- DCHECK(!dst.is(overflow_dst));
+void MacroAssembler::SubBranchOvf(Register dst, Register left, Register right,
+ Label* overflow_label,
+ Label* no_overflow_label, Register scratch) {
+ DCHECK(overflow_label || no_overflow_label);
+ Register overflow_dst = t9;
DCHECK(!dst.is(scratch));
- DCHECK(!overflow_dst.is(scratch));
+ DCHECK(!dst.is(overflow_dst));
+ DCHECK(!scratch.is(overflow_dst));
DCHECK(!overflow_dst.is(left));
DCHECK(!overflow_dst.is(right));
DCHECK(!scratch.is(left));
@@ -4406,8 +4459,9 @@ void MacroAssembler::SubuAndCheckForOverflow(Register dst, Register left,
// left == right, let's not make that restriction here.
if (left.is(right)) {
mov(dst, zero_reg);
- mov(overflow_dst, zero_reg);
- return;
+ if (no_overflow_label) {
+ Branch(no_overflow_label);
+ }
}
if (dst.is(left)) {
@@ -4428,6 +4482,7 @@ void MacroAssembler::SubuAndCheckForOverflow(Register dst, Register left,
xor_(scratch, left, right);
and_(overflow_dst, scratch, overflow_dst);
}
+ BranchOvfHelper(this, overflow_dst, overflow_label, no_overflow_label);
}
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