[VE] Support register and frame-index pair correctly

[kaz7]

Summary

Support register and frame-index pair correctly as operands of
generic load/store instrucitons, e.g. LD1BZXrri, STLrri, and etc.
Add regression tests also.

[simoll]

LGTM apart from the slightly convoluted test case.

llvm/test/CodeGen/VE/loadrri.ll

56–62

These types are only used to allocate a pointer (test func_rf) that is then immediately bitcast to the type below.
Couldn't we just allocate the type below directly? We could then remove the types, the bitcast and also simplify the name to something like basic_char_string.

[kaz7]

I'll update regression test.

llvm/test/CodeGen/VE/loadrri.ll

56–62

I think those unnecessary bit casts and types are the key of this regression test. I'll try to simplify this test little bit.

[kaz7]

Update a regression test belong to suggestion.

[simoll]

Thx

llvm/lib/Target/VE/VEISelDAGToDAG.cpp

if (matchADDRri(Addr, LHS, RHS)) {
     if (matchADDRrr(LHS, Base, Index)) {
       Offset = RHS;
       return true;
     }
     // Return false to try selectADDRrii.
     return false;
   }
   if (matchADDRrr(Addr, LHS, RHS)) {
+    // If the input is a pair of a frame-index and a register, move a
+    // frame-index to LHS.  This generates MI with following operands.
+    //    %dest, #FI, %reg, offset
+    // In the eliminateFrameIndex, above MI is converted to the following.
+    //    %dest, %fp, %reg, fi_offset + offset
+    if (dyn_cast<FrameIndexSDNode>(RHS))
+      std::swap(LHS, RHS);
+
     if (matchADDRri(RHS, Index, Offset)) {
       Base = LHS;
       return true;
     }
     if (matchADDRri(LHS, Base, Offset)) {
       Index = RHS;
       return true;
     }

llvm/test/CodeGen/VE/loadrri.ll

+; RUN: llc < %s -mtriple=ve | FileCheck %s
+
+%struct.data = type { [4 x i8] }
+
+;;; Check basic usage of rri format load instructions.
+;;; Our target is DAG selection mechanism for LD1BSXrri.
+;;; We prepared following three styles.
+;;;   1. LD1BSXrri with %reg1 + %reg2
+;;;   2. LD1BSXrri with %frame-index + %reg
+;;;   3. LD1BSXrri with %reg + %frame-index
+
+; Function Attrs: norecurse nounwind readonly
+define signext i8 @func_rr(%struct.data* nocapture readonly %0, i32 signext %1) {
+; CHECK-LABEL: func_rr:
+; CHECK:       .LBB{{[0-9]+}}_2:
+; CHECK-NEXT:    sll %s1, %s1, 2
+; CHECK-NEXT:    ld1b.sx %s0, (%s1, %s0)
+; CHECK-NEXT:    or %s11, 0, %s9
+  %3 = sext i32 %1 to i64
+  %4 = getelementptr inbounds %struct.data, %struct.data* %0, i64 %3, i32 0, i64 0
+  %5 = load i8, i8* %4, align 1
+  ret i8 %5
+}
+
+; Function Attrs: nounwind
+define signext i8 @func_fr(%struct.data* readonly %0, i32 signext %1) {
+; CHECK-LABEL: func_fr:
+; CHECK:       .LBB{{[0-9]+}}_2:
+; CHECK-NEXT:    sll %s1, %s1, 2
+; CHECK-NEXT:    ldl.sx %s0, (%s1, %s0)
+; CHECK-NEXT:    stl %s0, 184(%s1, %s11)
+; CHECK-NEXT:    ld1b.sx %s0, 184(%s1, %s11)
+; CHECK-NEXT:    or %s11, 0, %s9
+  %3 = alloca [10 x %struct.data], align 1
+  %4 = getelementptr inbounds [10 x %struct.data], [10 x %struct.data]* %3, i64 0, i64 0, i32 0, i64 0
+  call void @llvm.lifetime.start.p0i8(i64 40, i8* nonnull %4)
+  %5 = sext i32 %1 to i64
+  %6 = getelementptr inbounds [10 x %struct.data], [10 x %struct.data]* %3, i64 0, i64 %5, i32 0, i64 0
+  %7 = getelementptr inbounds %struct.data, %struct.data* %0, i64 %5, i32 0, i64 0
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull align 1 %6, i8* align 1 %7, i64 4, i1 true)
+  %8 = load volatile i8, i8* %6, align 1
+  call void @llvm.lifetime.end.p0i8(i64 40, i8* nonnull %4)
+  ret i8 %8
+}
+
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture)
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg)
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
+
+%"basic_string" = type { %union.anon.3, [23 x i8] }
+%union.anon.3 = type { i8 }
+
+define signext i8 @func_rf(i8* readonly %0, i64 %1, i32 signext %2) {
+; CHECK-LABEL: func_rf:
+; CHECK:       .LBB{{[0-9]+}}_2:
+; CHECK-NEXT:    ld1b.sx %s0, 184(%s1, %s11)
+; CHECK-NEXT:    or %s11, 0, %s9
+  %buf = alloca %"basic_string", align 8
+
+  %sub631 = add nsw i64 %1, -1
+  %add.ptr.i = getelementptr inbounds %"basic_string", %"basic_string"* %buf, i64 0, i32 1, i64 %sub631
+  %ret = load i8, i8* %add.ptr.i, align 1
+  ret i8 %ret
+}