[Turbofan] CodeGenerator for ARM avoids moves from VFP to general regs.

- Adds VmovExtended, VswpExtended methods to MacroAssembler. These methods
use only VFP registers to perform s-register moves.

LOG=N
BUG=v8:4124

Review-Url: https://codereview.chromium.org/2497483002
Cr-Commit-Position: refs/heads/master@{#40939}

src/arm/macro-assembler-arm.cc

@@ -1051,66 +1051,151 @@ void MacroAssembler::VmovLow(DwVfpRegister dst, Register src) {
   }
 }
 
-void MacroAssembler::VmovExtended(Register dst, int src_code) {
-  DCHECK_LE(32, src_code);
-  DCHECK_GT(64, src_code);
-  if (src_code & 0x1) {
-    VmovHigh(dst, DwVfpRegister::from_code(src_code / 2));
-  } else {
-    VmovLow(dst, DwVfpRegister::from_code(src_code / 2));
-  }
-}
-
-void MacroAssembler::VmovExtended(int dst_code, Register src) {
-  DCHECK_LE(32, dst_code);
-  DCHECK_GT(64, dst_code);
-  if (dst_code & 0x1) {
-    VmovHigh(DwVfpRegister::from_code(dst_code / 2), src);
-  } else {
-    VmovLow(DwVfpRegister::from_code(dst_code / 2), src);
-  }
-}
-
-void MacroAssembler::VmovExtended(int dst_code, int src_code,
-                                  Register scratch) {
+void MacroAssembler::VmovExtended(int dst_code, int src_code) {
   if (src_code < 32 && dst_code < 32) {
     // src and dst are both s-registers.
     vmov(SwVfpRegister::from_code(dst_code),
          SwVfpRegister::from_code(src_code));
   } else if (src_code < 32) {
-    // src is an s-register.
-    vmov(scratch, SwVfpRegister::from_code(src_code));
-    VmovExtended(dst_code, scratch);
+    // src is s-register, dst is in high d-register. Move dst into scratch
+    // d-register to do the s-register move, then back.
+    DCHECK_GT(64, dst_code);
+    DwVfpRegister dst_reg = DwVfpRegister::from_code(dst_code / 2);
+    int dst_s_code = kScratchDoubleReg.low().code() + (dst_code & 1);
+    vmov(kScratchDoubleReg, dst_reg);
+    vmov(SwVfpRegister::from_code(dst_s_code),
+         SwVfpRegister::from_code(src_code));
+    vmov(dst_reg, kScratchDoubleReg);
   } else if (dst_code < 32) {
-    // dst is an s-register.
-    VmovExtended(scratch, src_code);
-    vmov(SwVfpRegister::from_code(dst_code), scratch);
+    // src is in high d-register, dst is an s-register. Move src into scratch
+    // d-register, do the s-register move.
+    DCHECK_GT(64, src_code);
+    DwVfpRegister src_reg = DwVfpRegister::from_code(src_code / 2);
+    int src_s_code = kScratchDoubleReg.low().code() + (src_code & 1);
+    vmov(kScratchDoubleReg, src_reg);
+    vmov(SwVfpRegister::from_code(dst_code),
+         SwVfpRegister::from_code(src_s_code));
   } else {
-    // Neither src or dst are s-registers.
+    // src and dst are in high d-registers. Move both into free registers,
+    // do the s-register move, then move dst back.
     DCHECK_GT(64, src_code);
     DCHECK_GT(64, dst_code);
-    VmovExtended(scratch, src_code);
-    VmovExtended(dst_code, scratch);
+    DwVfpRegister dst_reg = DwVfpRegister::from_code(dst_code / 2);
+    DwVfpRegister src_reg = DwVfpRegister::from_code(src_code / 2);
+    int dst_s_code = kScratchDoubleReg.low().code() + (dst_code & 1);
+    int src_s_code = kDoubleRegZero.low().code() + (src_code & 1);
+    vmov(kScratchDoubleReg, dst_reg);
+    vmov(kDoubleRegZero, src_reg);
+    vmov(SwVfpRegister::from_code(dst_s_code),
+         SwVfpRegister::from_code(src_s_code));
+    vmov(dst_reg, kScratchDoubleReg);
+    vmov(kDoubleRegZero, 0.0);  // restore zero register
   }
 }
 
-void MacroAssembler::VmovExtended(int dst_code, const MemOperand& src,
-                                  Register scratch) {
-  if (dst_code >= 32) {
-    ldr(scratch, src);
-    VmovExtended(dst_code, scratch);
-  } else {
+void MacroAssembler::VmovExtended(int dst_code, const MemOperand& src) {
+  if (dst_code < 32) {
     vldr(SwVfpRegister::from_code(dst_code), src);
+  } else {
+    // dst is in high d-register, move it down, load src, then move it back up.
+    DCHECK_GT(64, dst_code);
+    DwVfpRegister dst_reg = DwVfpRegister::from_code(dst_code / 2);
+    int dst_s_code = kScratchDoubleReg.low().code() + (dst_code & 1);
+    vmov(kScratchDoubleReg, dst_reg);
+    vldr(SwVfpRegister::from_code(dst_s_code), src);
+    vmov(dst_reg, kScratchDoubleReg);
+  }
+}
+void MacroAssembler::VmovExtended(const MemOperand& dst, int src_code) {
+  if (src_code < 32) {
+    vstr(SwVfpRegister::from_code(src_code), dst);
+  } else {
+    // src is in high d-register, move it down, store src.
+    DCHECK_GT(64, src_code);
+    DwVfpRegister src_reg = DwVfpRegister::from_code(src_code / 2);
+    int src_s_code = kScratchDoubleReg.low().code() + (src_code & 1);
+    vmov(kScratchDoubleReg, src_reg);
+    vstr(SwVfpRegister::from_code(src_s_code), dst);
   }
 }
 
-void MacroAssembler::VmovExtended(const MemOperand& dst, int src_code,
-                                  Register scratch) {
-  if (src_code >= 32) {
-    VmovExtended(scratch, src_code);
-    str(scratch, dst);
+void MacroAssembler::VswpExtended(int dst_code, int src_code) {
+  if (src_code < 32 && dst_code < 32) {
+    // src and dst are both s-registers.
+    vmov(kScratchDoubleReg.low(), SwVfpRegister::from_code(dst_code));
+    vmov(SwVfpRegister::from_code(dst_code),
+         SwVfpRegister::from_code(src_code));
+    vmov(SwVfpRegister::from_code(src_code), kScratchDoubleReg.low());
+  } else if (src_code < 32) {
+    // src is s-register, dst is in high d-register. Move dst into scratch
+    // d-register to do the s-register swap, then back.
+    DCHECK_GT(64, dst_code);
+    DwVfpRegister dst_reg = DwVfpRegister::from_code(dst_code / 2);
+    int dst_s_code = kScratchDoubleReg.low().code() + (dst_code & 1);
+    int dst_s_temp = kDoubleRegZero.low().code() + (dst_code & 1);
+    vmov(kScratchDoubleReg, dst_reg);
+    vmov(kDoubleRegZero, dst_reg);
+    vmov(SwVfpRegister::from_code(dst_s_code),
+         SwVfpRegister::from_code(src_code));
+    vmov(dst_reg, kScratchDoubleReg);
+    vmov(SwVfpRegister::from_code(src_code),
+         SwVfpRegister::from_code(dst_s_temp));
+    vmov(kDoubleRegZero, 0.0);  // restore zero register
+  } else if (dst_code < 32) {
+    // src is in high d-register, dst is an s-register. Move src into scratch
+    // d-register, do the s-register swap.
+    DCHECK_GT(64, src_code);
+    DwVfpRegister src_reg = DwVfpRegister::from_code(src_code / 2);
+    int src_s_code = kScratchDoubleReg.low().code() + (src_code & 1);
+    int src_s_temp = kDoubleRegZero.low().code() + (src_code & 1);
+    vmov(kScratchDoubleReg, src_reg);
+    vmov(kDoubleRegZero, src_reg);
+    vmov(SwVfpRegister::from_code(src_s_code),
+         SwVfpRegister::from_code(dst_code));
+    vmov(src_reg, kScratchDoubleReg);
+    vmov(SwVfpRegister::from_code(dst_code),
+         SwVfpRegister::from_code(src_s_temp));
+    vmov(kDoubleRegZero, 0.0);  // restore zero register
   } else {
+    // src and dst are in high d-registers. Move both into free registers,
+    // do the s-register swap, then move both back.
+    DCHECK_GT(64, src_code);
+    DCHECK_GT(64, dst_code);
+    DwVfpRegister dst_reg = DwVfpRegister::from_code(dst_code / 2);
+    DwVfpRegister src_reg = DwVfpRegister::from_code(src_code / 2);
+    int dst_s_code = kScratchDoubleReg.low().code() + (dst_code & 1);
+    int src_s_code = kDoubleRegZero.low().code() + (src_code & 1);
+    vmov(kScratchDoubleReg, dst_reg);
+    vmov(kDoubleRegZero, src_reg);
+    vmov(SwVfpRegister::from_code(src_s_code ^ 1),
+         SwVfpRegister::from_code(dst_s_code));
+    vmov(SwVfpRegister::from_code(dst_s_code),
+         SwVfpRegister::from_code(src_s_code));
+    vmov(dst_reg, kScratchDoubleReg);
+    vmov(kScratchDoubleReg, src_reg);
+    vmov(SwVfpRegister::from_code(dst_s_code),
+         SwVfpRegister::from_code(src_s_code ^ 1));
+    vmov(src_reg, kScratchDoubleReg);
+    vmov(kDoubleRegZero, 0.0);  // restore zero register
+  }
+}
+
+void MacroAssembler::VswpExtended(const MemOperand& dst, int src_code) {
+  if (src_code < 32) {
+    vldr(kScratchDoubleReg.low(), dst);
     vstr(SwVfpRegister::from_code(src_code), dst);
+    vmov(SwVfpRegister::from_code(src_code), kScratchDoubleReg.low());
+  } else {
+    // src is in high d-register, move it down, do the swap, move src back up.
+    DCHECK_GT(64, src_code);
+    DwVfpRegister src_reg = DwVfpRegister::from_code(src_code / 2);
+    int src_s_code = kScratchDoubleReg.low().code() + (src_code & 1);
+    vmov(kScratchDoubleReg, src_reg);
+    vldr(kDoubleRegZero.low(), dst);
+    vstr(SwVfpRegister::from_code(src_s_code), dst);
+    vmov(SwVfpRegister::from_code(src_s_code), kDoubleRegZero.low());
+    vmov(src_reg, kScratchDoubleReg);
+    vmov(kDoubleRegZero, 0.0);  // restore zero register
   }
 }
 

src/arm/macro-assembler-arm.h

@@ -549,13 +549,12 @@ class MacroAssembler: public Assembler {
   void VmovLow(Register dst, DwVfpRegister src);
   void VmovLow(DwVfpRegister dst, Register src);
 
-  // Simulate s-register moves for imaginary s32 - s63 registers.
-  void VmovExtended(Register dst, int src_code);
-  void VmovExtended(int dst_code, Register src);
-  // Move between s-registers and imaginary s-registers.
-  void VmovExtended(int dst_code, int src_code, Register scratch);
-  void VmovExtended(int dst_code, const MemOperand& src, Register scratch);
-  void VmovExtended(const MemOperand& dst, int src_code, Register scratch);
+  // Simulate s-register moves and swaps for imaginary s32 - s63 registers.
+  void VmovExtended(int dst_code, int src_code);
+  void VmovExtended(int dst_code, const MemOperand& src);
+  void VmovExtended(const MemOperand& dst, int src_code);
+  void VswpExtended(int dst_code, int src_code);
+  void VswpExtended(const MemOperand& dst, int src_code);
 
   void LslPair(Register dst_low, Register dst_high, Register src_low,
                Register src_high, Register scratch, Register shift);

src/compiler/arm/code-generator-arm.cc

@@ -1898,10 +1898,10 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
       int src_code = LocationOperand::cast(source)->register_code();
       if (destination->IsFloatRegister()) {
         int dst_code = LocationOperand::cast(destination)->register_code();
-        __ VmovExtended(dst_code, src_code, kScratchReg);
+        __ VmovExtended(dst_code, src_code);
       } else {
         DCHECK(destination->IsFloatStackSlot());
-        __ VmovExtended(g.ToMemOperand(destination), src_code, kScratchReg);
+        __ VmovExtended(g.ToMemOperand(destination), src_code);
       }
     }
   } else if (source->IsFPStackSlot()) {
@@ -1916,7 +1916,7 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
         // GapResolver may give us reg codes that don't map to actual
         // s-registers. Generate code to work around those cases.
         int dst_code = LocationOperand::cast(destination)->register_code();
-        __ VmovExtended(dst_code, src, kScratchReg);
+        __ VmovExtended(dst_code, src);
       }
     } else {
       DCHECK(destination->IsFPStackSlot());
@@ -1988,15 +1988,11 @@ void CodeGenerator::AssembleSwap(InstructionOperand* source,
       int src_code = LocationOperand::cast(source)->register_code();
       if (destination->IsFPRegister()) {
         int dst_code = LocationOperand::cast(destination)->register_code();
-        __ VmovExtended(temp.low().code(), src_code, kScratchReg);
-        __ VmovExtended(src_code, dst_code, kScratchReg);
-        __ VmovExtended(dst_code, temp.low().code(), kScratchReg);
+        __ VswpExtended(dst_code, src_code);
       } else {
         DCHECK(destination->IsFPStackSlot());
         MemOperand dst = g.ToMemOperand(destination);
-        __ VmovExtended(temp.low().code(), src_code, kScratchReg);
-        __ VmovExtended(src_code, dst, kScratchReg);
-        __ vstr(temp.low(), dst);
+        __ VswpExtended(dst, src_code);
       }
     }
   } else if (source->IsFPStackSlot()) {