[turbofan] Fixed a bug in TryTruncateFloatXXToInt64 with INT64_MIN.

src/compiler/arm64/code-generator-arm64.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 "src/compiler/code-generator.h"
 
 #include "src/arm64/frames-arm64.h"
 #include "src/arm64/macro-assembler-arm64.h"
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator-impl.h"
@@ skipping 1027 matching lines @@
     case kArm64Float64ToUint32:
       __ Fcvtzu(i.OutputRegister32(), i.InputDoubleRegister(0));
       break;
     case kArm64Float32ToInt64:
       __ Fcvtzs(i.OutputRegister64(), i.InputFloat32Register(0));
       if (i.OutputCount() > 1) {
         __ Cmp(i.OutputRegister(0), 1);
         __ Ccmp(i.OutputRegister(0), -1, VFlag, vc);
         __ Fccmp(i.InputFloat32Register(0), i.InputFloat32Register(0), VFlag,
                  vc);
         __ Cset(i.OutputRegister(1), vc);

[jbramley, 2015/12/16 12:47:01]

This can now be a simple "__ Mov(i.OutputRegister(1), 1)". In the !vc case, it
gets overwritten anyway.

The same applies for Float64ToInt64.

[ahaas, 2015/12/16 14:35:23]

Done.

+        Label done;
+        __ B(vc, &done);
+        __ Fcmp(i.InputFloat32Register(0), -9223372036854775808.0f);

[jbramley, 2015/12/16 12:47:01]

Consider using "static_cast<float>(-INT64_MIN)" here to make the intention
clear.

[Michael Starzinger, 2015/12/16 13:01:29]

+1, magic number is being magic, please use a named value.

[ahaas, 2015/12/16 14:35:23]

Done.

+        __ Cset(i.OutputRegister(1), eq);
+        __ Bind(&done);
       }
       break;
     case kArm64Float64ToInt64:
       __ Fcvtzs(i.OutputRegister(0), i.InputDoubleRegister(0));
       if (i.OutputCount() > 1) {
         __ Cmp(i.OutputRegister(0), 1);
         __ Ccmp(i.OutputRegister(0), -1, VFlag, vc);
         __ Fccmp(i.InputDoubleRegister(0), i.InputDoubleRegister(0), VFlag, vc);
         __ Cset(i.OutputRegister(1), vc);
+        Label done;
+        __ B(vc, &done);
+        __ Fcmp(i.InputDoubleRegister(0), -9223372036854775808.0f);

[jbramley, 2015/12/16 12:47:01]

Ditto. (Otherwise, remove the "f" since this is a double.)

[Michael Starzinger, 2015/12/16 13:01:29]

+1

[ahaas, 2015/12/16 14:35:23]

Done.

+        __ Cset(i.OutputRegister(1), eq);
+        __ Bind(&done);
       }
       break;
     case kArm64Float32ToUint64:
       __ Fcvtzu(i.OutputRegister64(), i.InputFloat32Register(0));
       if (i.OutputCount() > 1) {
         __ Fcmp(i.InputFloat32Register(0), 0.0);
         __ Ccmp(i.OutputRegister(0), -1, ZFlag, ge);
         __ Cset(i.OutputRegister(1), ne);
       }
       break;
@@ skipping 553 matching lines @@
       padding_size -= kInstructionSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8