[wasm] Int64Lowering of I64ShrU and I64ShrS on ia32.

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 4e421176c0705b267772261e7df2efb8588085ab..074992d7f217e853362352e2a08fddd34008e33a 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -728,6 +728,50 @@ void MacroAssembler::PairShl_cl(Register dst, Register src) {
   bind(&done);
 }
 
+void MacroAssembler::PairShr(Register dst, Register src, uint8_t shift) {

[titzer, 2016/03/07 19:25:35]

{dst} and {src} are misnamed. They should be {hi} and {lo}, and they are
modified in place.

[ahaas, 2016/03/08 07:58:42]

Done.

+  if (shift >= 32) {
+    mov(src, dst);
+    shr(src, shift - 32);
+    xor_(dst, dst);
+  } else {
+    shrd(dst, src, shift);
+    shr(dst, shift);
+  }
+}
+
+void MacroAssembler::PairShr_cl(Register dst, Register src) {
+  shrd_cl(dst, src);
+  shr_cl(dst);
+  Label done;
+  test(ecx, Immediate(0x20));
+  j(equal, &done, Label::kNear);
+  mov(src, dst);
+  xor_(dst, dst);
+  bind(&done);
+}
+
+void MacroAssembler::PairSar(Register dst, Register src, uint8_t shift) {
+  if (shift >= 32) {
+    mov(src, dst);
+    sar(src, shift - 32);
+    sar(dst, 31);
+  } else {
+    shrd(dst, src, shift);
+    sar(dst, shift);
+  }
+}
+
+void MacroAssembler::PairSar_cl(Register dst, Register src) {
+  shrd_cl(dst, src);
+  sar_cl(dst);
+  Label done;
+  test(ecx, Immediate(0x20));
+  j(equal, &done, Label::kNear);
+  mov(src, dst);
+  sar(dst, 31);
+  bind(&done);
+}
+
 bool MacroAssembler::IsUnsafeImmediate(const Immediate& x) {
   static const int kMaxImmediateBits = 17;
   if (!RelocInfo::IsNone(x.rmode_)) return false;