[Liftoff][mips] Implement eqz operations

Optimize initial implementation of i32_eqz and implement i64_eqz.

Bug: v8:6600
Change-Id: I695454a160fc57dc9981725583ed2f27c2c537db
Reviewed-on: https://chromium-review.googlesource.com/978207Reviewed-by: Ivica Bogosavljevic <ivica.bogosavljevic@mips.com>
Commit-Queue: Ivica Bogosavljevic <ivica.bogosavljevic@mips.com>
Cr-Commit-Position: refs/heads/master@{#52189}

src/wasm/baseline/mips/liftoff-assembler-mips.h

@@ -556,25 +556,7 @@ void LiftoffAssembler::emit_cond_jump(Condition cond, Label* label,
 }
 
 void LiftoffAssembler::emit_i32_eqz(Register dst, Register src) {
-  Label true_label;
-  if (dst != src) {
-    ori(dst, zero_reg, 0x1);
-  }
-
-  TurboAssembler::Branch(&true_label, eq, src, Operand(zero_reg));
-  // If not true, set on 0.
-  TurboAssembler::mov(dst, zero_reg);
-
-  if (dst != src) {
-    bind(&true_label);
-  } else {
-    Label end_label;
-    TurboAssembler::Branch(&end_label);
-    bind(&true_label);
-
-    ori(dst, zero_reg, 0x1);
-    bind(&end_label);
-  }
+  sltiu(dst, src, 1);
 }
 
 void LiftoffAssembler::emit_i32_set_cond(Condition cond, Register dst,
@@ -601,7 +583,11 @@ void LiftoffAssembler::emit_i32_set_cond(Condition cond, Register dst,
 }
 
 void LiftoffAssembler::emit_i64_eqz(Register dst, LiftoffRegister src) {
-  BAILOUT("emit_i64_eqz");
+  Register tmp =
+      GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(src, dst)).gp();
+  sltiu(tmp, src.low_gp(), 1);
+  sltiu(dst, src.high_gp(), 1);
+  and_(dst, dst, tmp);
 }
 
 void LiftoffAssembler::emit_i64_set_cond(Condition cond, Register dst,

src/wasm/baseline/mips64/liftoff-assembler-mips64.h

@@ -450,25 +450,7 @@ void LiftoffAssembler::emit_cond_jump(Condition cond, Label* label,
 }
 
 void LiftoffAssembler::emit_i32_eqz(Register dst, Register src) {
-  Label true_label;
-  if (dst != src) {
-    ori(dst, zero_reg, 0x1);
-  }
-
-  TurboAssembler::Branch(&true_label, eq, src, Operand(zero_reg));
-  // If not true, set on 0.
-  TurboAssembler::mov(dst, zero_reg);
-
-  if (dst != src) {
-    bind(&true_label);
-  } else {
-    Label end_label;
-    TurboAssembler::Branch(&end_label);
-    bind(&true_label);
-
-    ori(dst, zero_reg, 0x1);
-    bind(&end_label);
-  }
+  sltiu(dst, src, 1);
 }
 
 void LiftoffAssembler::emit_i32_set_cond(Condition cond, Register dst,
@@ -495,7 +477,7 @@ void LiftoffAssembler::emit_i32_set_cond(Condition cond, Register dst,
 }
 
 void LiftoffAssembler::emit_i64_eqz(Register dst, LiftoffRegister src) {
-  BAILOUT("emit_i64_eqz");
+  sltiu(dst, src.gp(), 1);
 }
 
 void LiftoffAssembler::emit_i64_set_cond(Condition cond, Register dst,