[CGBuiltin] Explicitly use inbounds GEP (NFCI)

All of these are inbounds as they access known offsets in fixed
globals. NFCI because constant expression construction currently
already infers this, this patch just makes it explicit.

Author: nikic

clang/lib/CodeGen/CGBuiltin.cpp

@@ -14074,7 +14074,7 @@ Value *CodeGenFunction::EmitX86CpuIs(StringRef CPUStr) {
   // Grab the appropriate field from __cpu_model.
   llvm::Value *Idxs[] = {ConstantInt::get(Int32Ty, 0),
                          ConstantInt::get(Int32Ty, Index)};
-  llvm::Value *CpuValue = Builder.CreateGEP(STy, CpuModel, Idxs);
+  llvm::Value *CpuValue = Builder.CreateInBoundsGEP(STy, CpuModel, Idxs);
   CpuValue = Builder.CreateAlignedLoad(Int32Ty, CpuValue,
                                        CharUnits::fromQuantity(4));
 
@@ -14116,7 +14116,7 @@ CodeGenFunction::EmitX86CpuSupports(std::array<uint32_t, 4> FeatureMask) {
     // global in the struct STy.
     Value *Idxs[] = {Builder.getInt32(0), Builder.getInt32(3),
                      Builder.getInt32(0)};
-    Value *CpuFeatures = Builder.CreateGEP(STy, CpuModel, Idxs);
+    Value *CpuFeatures = Builder.CreateInBoundsGEP(STy, CpuModel, Idxs);
     Value *Features = Builder.CreateAlignedLoad(Int32Ty, CpuFeatures,
                                                 CharUnits::fromQuantity(4));
 
@@ -14137,7 +14137,7 @@ CodeGenFunction::EmitX86CpuSupports(std::array<uint32_t, 4> FeatureMask) {
       continue;
     Value *Idxs[] = {Builder.getInt32(0), Builder.getInt32(i - 1)};
     Value *Features = Builder.CreateAlignedLoad(
-        Int32Ty, Builder.CreateGEP(ATy, CpuFeatures2, Idxs),
+        Int32Ty, Builder.CreateInBoundsGEP(ATy, CpuFeatures2, Idxs),
         CharUnits::fromQuantity(4));
     // Check the value of the bit corresponding to the feature requested.
     Value *Mask = Builder.getInt32(M);
@@ -16724,7 +16724,7 @@ Value *CodeGenFunction::EmitPPCBuiltinExpr(unsigned BuiltinID,
       llvm::Value *Idxs[] = {ConstantInt::get(Int32Ty, 0),
                              ConstantInt::get(Int32Ty, FieldIdx)};
 
-      FieldValue = Builder.CreateGEP(STy, SysConf, Idxs);
+      FieldValue = Builder.CreateInBoundsGEP(STy, SysConf, Idxs);
       FieldValue = Builder.CreateAlignedLoad(Int32Ty, FieldValue,
                                              CharUnits::fromQuantity(4));
     } else if (SupportMethod == SYS_CALL) {