Refine Word32Pair* shift code generation.

src/ppc/macro-assembler-ppc.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <assert.h>  // For assert
 #include <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #if V8_TARGET_ARCH_PPC
 
 #include "src/base/bits.h"
@@ skipping 842 matching lines @@
   orx(dst_high, dst_high, scratch);
   slw(dst_low, src_low, shift);
   bind(&done);
 }
 
 void MacroAssembler::ShiftLeftPair(Register dst_low, Register dst_high,
                                    Register src_low, Register src_high,
                                    uint32_t shift) {
   DCHECK(!AreAliased(dst_low, src_high));
   DCHECK(!AreAliased(dst_high, src_low));
-  if (shift >= 32) {
+  if (shift == 32) {
+    Move(dst_high, src_low);
+    li(dst_low, Operand::Zero());
+  } else if (shift > 32) {
     shift &= 0x1f;
     slwi(dst_high, src_low, Operand(shift));
     li(dst_low, Operand::Zero());
   } else if (shift == 0) {
     Move(dst_low, src_low);
     Move(dst_high, src_high);
   } else {
     slwi(dst_high, src_high, Operand(shift));
     rlwimi(dst_high, src_low, shift, 32 - shift, 31);
     slwi(dst_low, src_low, Operand(shift));
@@ skipping 22 matching lines @@
   orx(dst_low, dst_low, scratch);
   srw(dst_high, src_high, shift);
   bind(&done);
 }
 
 void MacroAssembler::ShiftRightPair(Register dst_low, Register dst_high,
                                     Register src_low, Register src_high,
                                     uint32_t shift) {
   DCHECK(!AreAliased(dst_low, src_high));
   DCHECK(!AreAliased(dst_high, src_low));
-  if (shift >= 32) {
+  if (shift == 32) {
+    Move(dst_low, src_high);
+    li(dst_high, Operand::Zero());
+  } else if (shift > 32) {
     shift &= 0x1f;
     srwi(dst_low, src_high, Operand(shift));
     li(dst_high, Operand::Zero());
   } else if (shift == 0) {
     Move(dst_low, src_low);
     Move(dst_high, src_high);
   } else {
     srwi(dst_low, src_low, Operand(shift));
     rlwimi(dst_low, src_high, 32 - shift, 0, shift - 1);
     srwi(dst_high, src_high, Operand(shift));
@@ skipping 22 matching lines @@
   orx(dst_low, dst_low, scratch);
   sraw(dst_high, src_high, shift);
   bind(&done);
 }
 
 void MacroAssembler::ShiftRightAlgPair(Register dst_low, Register dst_high,
                                        Register src_low, Register src_high,
                                        uint32_t shift) {
   DCHECK(!AreAliased(dst_low, src_high));
   DCHECK(!AreAliased(dst_high, src_low));
-  if (shift >= 32) {
+  if (shift == 32) {
+    Move(dst_low, src_high);
+    srawi(dst_high, src_high, 31);
+  } else if (shift > 32) {
     shift &= 0x1f;
     srawi(dst_low, src_high, shift);
     srawi(dst_high, src_high, 31);
   } else if (shift == 0) {
     Move(dst_low, src_low);
     Move(dst_high, src_high);
   } else {
     srwi(dst_low, src_low, Operand(shift));
     rlwimi(dst_low, src_high, 32 - shift, 0, shift - 1);
     srawi(dst_high, src_high, shift);
@@ skipping 3661 matching lines @@
   }
   if (mag.shift > 0) srawi(result, result, mag.shift);
   ExtractBit(r0, dividend, 31);
   add(result, result, r0);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_PPC