[turbofan] Fixed the second return value of TryTruncateFloatXXToUint64.

As required by the spec, the second return value now returns success
also for the range between 0 and -1 where the conversion results in 0.

R=bradnelson@chromium.org, mstarzinger@chromium.org, v8-arm-ports@googlegroups.com, v8-mips-ports@googlegroups.com

Review URL: https://codereview.chromium.org/1533503002

Cr-Commit-Position: refs/heads/master@{#32936}

src/compiler/arm64/code-generator-arm64.cc

@@ -1070,16 +1070,16 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     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);
+        __ Fcmp(i.InputFloat32Register(0), -1.0);
+        __ Ccmp(i.OutputRegister(0), -1, ZFlag, gt);
         __ Cset(i.OutputRegister(1), ne);
       }
       break;
     case kArm64Float64ToUint64:
       __ Fcvtzu(i.OutputRegister64(), i.InputDoubleRegister(0));
       if (i.OutputCount() > 1) {
-        __ Fcmp(i.InputDoubleRegister(0), 0.0);
-        __ Ccmp(i.OutputRegister(0), -1, ZFlag, ge);
+        __ Fcmp(i.InputDoubleRegister(0), -1.0);
+        __ Ccmp(i.OutputRegister(0), -1, ZFlag, gt);
         __ Cset(i.OutputRegister(1), ne);
       }
       break;

src/compiler/x64/code-generator-x64.cc

@@ -1109,14 +1109,6 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       Label success;
       if (instr->OutputCount() > 1) {
         __ Set(i.OutputRegister(1), 0);
-        __ xorps(kScratchDoubleReg, kScratchDoubleReg);
-
-        if (instr->InputAt(0)->IsDoubleRegister()) {
-          __ Ucomiss(kScratchDoubleReg, i.InputDoubleRegister(0));
-        } else {
-          __ Ucomiss(kScratchDoubleReg, i.InputOperand(0));
-        }
-        __ j(above, &done);
       }
       // There does not exist a Float32ToUint64 instruction, so we have to use
       // the Float32ToInt64 instruction.
@@ -1160,14 +1152,6 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       Label success;
       if (instr->OutputCount() > 1) {
         __ Set(i.OutputRegister(1), 0);
-        __ xorps(kScratchDoubleReg, kScratchDoubleReg);
-
-        if (instr->InputAt(0)->IsDoubleRegister()) {
-          __ Ucomisd(kScratchDoubleReg, i.InputDoubleRegister(0));
-        } else {
-          __ Ucomisd(kScratchDoubleReg, i.InputOperand(0));
-        }
-        __ j(above, &done);
       }
       // There does not exist a Float64ToUint64 instruction, so we have to use
       // the Float64ToInt64 instruction.

src/mips64/macro-assembler-mips64.cc

@@ -1705,9 +1705,9 @@ void MacroAssembler::Trunc_ul_d(FPURegister fd, Register rs,
   Label simple_convert, done, fail;
   if (result.is_valid()) {
     mov(result, zero_reg);
-    Move(kDoubleRegZero, 0.0);
-    // If fd < 0 or unordered, then the conversion fails.
-    BranchF(&fail, &fail, lt, fd, kDoubleRegZero);
+    Move(scratch, -1.0);
+    // If fd =< -1 or unordered, then the conversion fails.
+    BranchF(&fail, &fail, le, fd, scratch);
   }
 
   // Load 2^63 into scratch as its double representation.
@@ -1753,9 +1753,9 @@ void MacroAssembler::Trunc_ul_s(FPURegister fd, Register rs,
   Label simple_convert, done, fail;
   if (result.is_valid()) {
     mov(result, zero_reg);
-    Move(kDoubleRegZero, 0.0);
-    // If fd < 0 or unordered, then the conversion fails.
-    BranchF32(&fail, &fail, lt, fd, kDoubleRegZero);
+    Move(scratch, -1.0f);
+    // If fd =< -1 or unordered, then the conversion fails.
+    BranchF32(&fail, &fail, le, fd, scratch);
   }
 
   // Load 2^63 into scratch as its float representation.

test/cctest/compiler/test-run-machops.cc

@@ -5529,21 +5529,18 @@ TEST(RunTryTruncateFloat64ToInt64WithCheck) {
 }
 
 
-TEST(RunTruncateFloat32ToUint64) {
+TEST(RunTryTruncateFloat32ToUint64WithoutCheck) {
   BufferedRawMachineAssemblerTester<uint64_t> m(MachineType::Float32());
   m.Return(m.TryTruncateFloat32ToUint64(m.Parameter(0)));
 
   FOR_UINT64_INPUTS(i) {
     float input = static_cast<float>(*i);
-    if (input < 18446744073709551616.0) {
+    // This condition on 'input' is required because
+    // static_cast<float>(UINT64_MAX) results in a value outside uint64 range.
+    if (input < static_cast<float>(UINT64_MAX)) {
       CHECK_EQ(static_cast<uint64_t>(input), m.Call(input));
     }
   }
-  FOR_FLOAT32_INPUTS(j) {
-    if (*j < 18446744073709551616.0 && *j >= 0) {
-      CHECK_EQ(static_cast<uint64_t>(*j), m.Call(*j));
-    }
-  }
 }
 
 
@@ -5557,7 +5554,7 @@ TEST(RunTryTruncateFloat32ToUint64WithCheck) {
   m.Return(val);
 
   FOR_FLOAT32_INPUTS(i) {
-    if (*i < 18446744073709551616.0 && *i >= 0.0) {
+    if (*i < static_cast<float>(UINT64_MAX) && *i > -1.0) {
       // Conversions within this range should succeed.
       CHECK_EQ(static_cast<uint64_t>(*i), m.Call(*i));
       CHECK_NE(0, success);
@@ -5576,7 +5573,7 @@ TEST(RunTryTruncateFloat64ToUint64WithoutCheck) {
   FOR_UINT64_INPUTS(j) {
     double input = static_cast<double>(*j);
 
-    if (input < 18446744073709551616.0) {
+    if (input < static_cast<float>(UINT64_MAX)) {
       CHECK_EQ(static_cast<uint64_t>(input), m.Call(input));
     }
   }
@@ -5593,7 +5590,7 @@ TEST(RunTryTruncateFloat64ToUint64WithCheck) {
   m.Return(val);
 
   FOR_FLOAT64_INPUTS(i) {
-    if (*i < 18446744073709551616.0 && *i >= 0) {
+    if (*i < 18446744073709551616.0 && *i > -1) {
       // Conversions within this range should succeed.
       CHECK_EQ(static_cast<uint64_t>(*i), m.Call(*i));
       CHECK_NE(0, success);

test/cctest/compiler/value-helper.h

@@ -104,6 +104,7 @@ class ValueHelper {
         -62.0f,
         -15.0f,
         -7.0f,
+        -1.0f,
         -0.0256635f,
         -4.60374e-07f,
         -3.63759e-10f,
@@ -133,6 +134,7 @@ class ValueHelper {
         5.57888e-07f,
         4.89988e-05f,
         0.244326f,
+        1.0f,
         12.4895f,
         19.0f,
         47.0f,
@@ -186,6 +188,7 @@ class ValueHelper {
                                     -999.75,
                                     -2e66,
                                     -1.75,
+                                    -1.0,
                                     -0.5,
                                     -0.0,
                                     0.0,
@@ -194,6 +197,7 @@ class ValueHelper {
                                     0.25,
                                     0.375,
                                     0.5,
+                                    1.0,
                                     1.25,
                                     2,
                                     3.1e7,

test/cctest/wasm/test-run-wasm.cc

@@ -3408,7 +3408,7 @@ TEST(Run_Wasm_I64UConvertF32) {
   BUILD(r, WASM_I64_UCONVERT_F32(WASM_GET_LOCAL(0)));
 
   FOR_FLOAT32_INPUTS(i) {
-    if (*i < 18446744073709551616.0 && *i >= 0) {
+    if (*i < static_cast<float>(UINT64_MAX) && *i > -1) {
       CHECK_EQ(static_cast<uint64_t>(*i), r.Call(*i));
     } else {
       CHECK_TRAP64(r.Call(*i));
@@ -3422,7 +3422,7 @@ TEST(Run_Wasm_I64UConvertF64) {
   BUILD(r, WASM_I64_UCONVERT_F64(WASM_GET_LOCAL(0)));
 
   FOR_FLOAT64_INPUTS(i) {
-    if (*i < 18446744073709551616.0 && *i >= 0) {
+    if (*i < static_cast<float>(UINT64_MAX) && *i > -1) {
       CHECK_EQ(static_cast<uint64_t>(*i), r.Call(*i));
     } else {
       CHECK_TRAP64(r.Call(*i));