S390X: [turbofan] Fix checked loads/stores.

This refines 6382a610 -- as we still
require clean up of the uint index register.

TEST=mjsunit/asm/float32array-negative-offset
R=joransiu@ca.ibm.com, mbrandy@us.ibm.com, michael_dawson@ca.ibm.com, bjaideep@ca.ibm.com
BUG=

Conflicts:
	src/compiler/s390/code-generator-s390.cc

Review-Url: https://codereview.chromium.org/1921073003
Cr-Commit-Position: refs/heads/master@{#35879}

src/compiler/s390/code-generator-s390.cc

@@ -466,6 +466,7 @@ Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
     }                                                              \
     auto ool = new (zone()) OutOfLineLoadNAN##width(this, result); \
     __ bge(ool->entry());                                          \
+    __ CleanUInt32(offset);                                        \
     __ asm_instr(result, operand);                                 \
     __ bind(ool->exit());                                          \
   } while (0)
@@ -484,6 +485,7 @@ Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
     }                                                        \
     auto ool = new (zone()) OutOfLineLoadZero(this, result); \
     __ bge(ool->entry());                                    \
+    __ CleanUInt32(offset);                                  \
     __ asm_instr(result, operand);                           \
     __ bind(ool->exit());                                    \
   } while (0)
@@ -502,6 +504,7 @@ Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
     }                                                   \
     __ bge(&done);                                      \
     DoubleRegister value = i.InputDoubleRegister(3);    \
+    __ CleanUInt32(offset);                             \
     __ StoreFloat32(value, operand);                    \
     __ bind(&done);                                     \
   } while (0)
@@ -521,6 +524,7 @@ Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
     }                                                   \
     __ bge(&done);                                      \
     DoubleRegister value = i.InputDoubleRegister(3);    \
+    __ CleanUInt32(offset);                             \
     __ StoreDouble(value, operand);                     \
     __ bind(&done);                                     \
   } while (0)
@@ -539,6 +543,7 @@ Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
     }                                                   \
     __ bge(&done);                                      \
     Register value = i.InputRegister(3);                \
+    __ CleanUInt32(offset);                             \
     __ asm_instr(value, operand);                       \
     __ bind(&done);                                     \
   } while (0)

src/s390/macro-assembler-s390.h

@@ -412,6 +412,12 @@ class MacroAssembler : public Assembler {
 
   void mov(Register dst, const Operand& src);
 
+  void CleanUInt32(Register x) {
+#ifdef V8_TARGET_ARCH_S390X
+    llgfr(x, x);
+#endif
+  }
+
   // ---------------------------------------------------------------------------
   // GC Support