[sve] Fix the index specifier decoding error in the gather load helper.

In the simulation of the scalar-plus-vector form of gather loads,
the helper hasn't considered shift specifiers in the decoding, so
64-bit unscaled/scaled offset forms haven't been generated and tested.

Change-Id: If4539de5a1b4e6760780fdbaefd56dc84dd47413

3 files changed, 18 insertions, 10 deletions

diff --git a/src/aarch64/logic-aarch64.cc b/src/aarch64/logic-aarch64.cc
index 3ac41e2f..9684355a 100644
--- a/src/aarch64/logic-aarch64.cc
+++ b/src/aarch64/logic-aarch64.cc
@@ -7262,14 +7262,14 @@ void Simulator::SVEFaultTolerantLoadHelper(VectorFormat vform,
 }
 
 void Simulator::SVEGatherLoadScalarPlusVectorHelper(const Instruction* instr,
-                                                    VectorFormat vform) {
+                                                    VectorFormat vform,
+                                                    SVEOffsetModifier mod) {
   bool is_signed = instr->ExtractBit(14) == 0;
   bool is_ff = instr->ExtractBit(13) == 1;
   // Note that these instructions don't use the Dtype encoding.
   int msize_in_bytes_log2 = instr->ExtractBits(24, 23);
   int scale = instr->ExtractBit(21) * msize_in_bytes_log2;
   uint64_t base = ReadXRegister(instr->GetRn());
-  SVEOffsetModifier mod = (instr->ExtractBit(22) == 1) ? SVE_SXTW : SVE_UXTW;
   LogicSVEAddressVector addr(base,
                              &ReadVRegister(instr->GetRm()),
                              vform,
diff --git a/src/aarch64/simulator-aarch64.cc b/src/aarch64/simulator-aarch64.cc
index 9b69fcea..d0fa2b90 100644
--- a/src/aarch64/simulator-aarch64.cc
+++ b/src/aarch64/simulator-aarch64.cc
@@ -9540,7 +9540,8 @@ void Simulator::VisitSVE32BitGatherLoadHalfwords_ScalarPlus32BitScaledOffsets(
       break;
   }
 
-  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnS);
+  SVEOffsetModifier mod = (instr->ExtractBit(22) == 1) ? SVE_SXTW : SVE_UXTW;
+  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnS, mod);
 }
 
 void Simulator::VisitSVE32BitGatherLoad_ScalarPlus32BitUnscaledOffsets(
@@ -9563,7 +9564,8 @@ void Simulator::VisitSVE32BitGatherLoad_ScalarPlus32BitUnscaledOffsets(
       break;
   }
 
-  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnS);
+  SVEOffsetModifier mod = (instr->ExtractBit(22) == 1) ? SVE_SXTW : SVE_UXTW;
+  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnS, mod);
 }
 
 void Simulator::VisitSVE32BitGatherLoad_VectorPlusImm(
@@ -9619,7 +9621,8 @@ void Simulator::VisitSVE32BitGatherLoadWords_ScalarPlus32BitScaledOffsets(
       break;
   }
 
-  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnS);
+  SVEOffsetModifier mod = (instr->ExtractBit(22) == 1) ? SVE_SXTW : SVE_UXTW;
+  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnS, mod);
 }
 
 void Simulator::VisitSVE32BitGatherPrefetch_ScalarPlus32BitScaledOffsets(
@@ -9805,7 +9808,8 @@ void Simulator::VisitSVE64BitGatherLoad_ScalarPlus32BitUnpackedScaledOffsets(
       break;
   }
 
-  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnD);
+  SVEOffsetModifier mod = (instr->ExtractBit(22) == 1) ? SVE_SXTW : SVE_UXTW;
+  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnD, mod);
 }
 
 void Simulator::VisitSVE64BitGatherLoad_ScalarPlus64BitScaledOffsets(
@@ -9838,7 +9842,7 @@ void Simulator::VisitSVE64BitGatherLoad_ScalarPlus64BitScaledOffsets(
       break;
   }
 
-  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnD);
+  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnD, SVE_LSL);
 }
 
 void Simulator::VisitSVE64BitGatherLoad_ScalarPlus64BitUnscaledOffsets(
@@ -9865,7 +9869,9 @@ void Simulator::VisitSVE64BitGatherLoad_ScalarPlus64BitUnscaledOffsets(
       break;
   }
 
-  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnD);
+  SVEGatherLoadScalarPlusVectorHelper(instr,
+                                      kFormatVnD,
+                                      NO_SVE_OFFSET_MODIFIER);
 }
 
 void Simulator::VisitSVE64BitGatherLoad_ScalarPlusUnpacked32BitUnscaledOffsets(
@@ -9907,7 +9913,8 @@ void Simulator::VisitSVE64BitGatherLoad_ScalarPlusUnpacked32BitUnscaledOffsets(
       break;
   }
 
-  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnD);
+  SVEOffsetModifier mod = (instr->ExtractBit(22) == 1) ? SVE_SXTW : SVE_UXTW;
+  SVEGatherLoadScalarPlusVectorHelper(instr, kFormatVnD, mod);
 }
 
 void Simulator::VisitSVE64BitGatherLoad_VectorPlusImm(
diff --git a/src/aarch64/simulator-aarch64.h b/src/aarch64/simulator-aarch64.h
index bfb1c500..1a89dff7 100644
--- a/src/aarch64/simulator-aarch64.h
+++ b/src/aarch64/simulator-aarch64.h
@@ -4362,7 +4362,8 @@ class Simulator : public DecoderVisitor {
                                             FlagsUpdate flags = SetFlags);
 
   void SVEGatherLoadScalarPlusVectorHelper(const Instruction* instr,
-                                           VectorFormat vform);
+                                           VectorFormat vform,
+                                           SVEOffsetModifier mod);
 
   // Store each active zt<i>[lane] to `addr.GetElementAddress(lane, ...)`.
   //