ARM: optimize inlined doubles

src/arm/assembler-arm.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 2527 matching lines @@
       vldr(dst, MemOperand(pp, ip));
     } else {
       DCHECK(section == ConstantPoolArray::SMALL_SECTION);
       vldr(dst, MemOperand(FLAG_enable_ool_constant_pool ? pp : pc, 0));
     }
   } else {
     // Synthesise the double from ARM immediates.
     uint32_t lo, hi;
     DoubleAsTwoUInt32(imm, &lo, &hi);
 
-    if (scratch.is(no_reg)) {
-      if (dst.code() < 16) {
-        const LowDwVfpRegister loc = LowDwVfpRegister::from_code(dst.code());
-        // Move the low part of the double into the lower of the corresponsing S
-        // registers of D register dst.
-        mov(ip, Operand(lo));
-        vmov(loc.low(), ip);
-
-        // Move the high part of the double into the higher of the
-        // corresponsing S registers of D register dst.
+    if (lo == hi) {
+      // Move the low and high parts of the double to a D register in one
+      // instruction.
+      mov(ip, Operand(lo));
+      vmov(dst, ip, ip);
+    } else if (scratch.is(no_reg)) {
+      mov(ip, Operand(lo));
+      vmov(dst, VmovIndexLo, ip);
+      if ((lo & 0xffff) == (hi & 0xffff)) {
+        movt(ip, hi >> 16);
+      } else {
         mov(ip, Operand(hi));
-        vmov(loc.high(), ip);
-      } else {
-        // D16-D31 does not have S registers, so move the low and high parts
-        // directly to the D register using vmov.32.
-        // Note: This may be slower, so we only do this when we have to.
-        mov(ip, Operand(lo));
-        vmov(dst, VmovIndexLo, ip);
-        mov(ip, Operand(hi));
-        vmov(dst, VmovIndexHi, ip);
       }
+      vmov(dst, VmovIndexHi, ip);
     } else {
       // Move the low and high parts of the double to a D register in one
       // instruction.
       mov(ip, Operand(lo));
       mov(scratch, Operand(hi));
       vmov(dst, ip, scratch);
     }
   }
 }
 
@@ skipping 1345 matching lines @@
       assm->instr_at_put(
           rinfo.pc(), Assembler::SetLdrRegisterImmediateOffset(instr, offset));
     }
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM