Add tests for diff of splat geps

Author: nikic

llvm/test/Transforms/InstCombine/sub-gep.ll

@@ -995,3 +995,39 @@ define i64 @multiple_geps_inbounds_nuw(ptr %base, i64 %idx, i64 %idx2) {
   %d = sub i64 %i2, %i1
   ret i64 %d
 }
+
+define <2 x i64> @splat_geps(ptr %base, <2 x i64> %idx1, <2 x i64> %idx2) {
+; CHECK-LABEL: @splat_geps(
+; CHECK-NEXT:    [[GEP1:%.*]] = getelementptr inbounds i8, ptr [[BASE:%.*]], <2 x i64> [[IDX1:%.*]]
+; CHECK-NEXT:    [[GEP2:%.*]] = getelementptr inbounds i8, ptr [[BASE]], <2 x i64> [[IDX2:%.*]]
+; CHECK-NEXT:    [[GEP1_INT:%.*]] = ptrtoint <2 x ptr> [[GEP1]] to <2 x i64>
+; CHECK-NEXT:    [[GEP2_INT:%.*]] = ptrtoint <2 x ptr> [[GEP2]] to <2 x i64>
+; CHECK-NEXT:    [[D:%.*]] = sub <2 x i64> [[GEP2_INT]], [[GEP1_INT]]
+; CHECK-NEXT:    ret <2 x i64> [[D]]
+;
+  %gep1 = getelementptr inbounds i8, ptr %base, <2 x i64> %idx1
+  %gep2 = getelementptr inbounds i8, ptr %base, <2 x i64> %idx2
+  %gep1.int = ptrtoint <2 x ptr> %gep1 to <2 x i64>
+  %gep2.int = ptrtoint <2 x ptr> %gep2 to <2 x i64>
+  %d = sub <2 x i64> %gep2.int, %gep1.int
+  ret <2 x i64> %d
+}
+
+define <2 x i64> @splat_geps_multiple(ptr %base, i64 %idx0, <2 x i64> %idx1, <2 x i64> %idx2) {
+; CHECK-LABEL: @splat_geps_multiple(
+; CHECK-NEXT:    [[GEP0:%.*]] = getelementptr inbounds i8, ptr [[BASE:%.*]], i64 [[IDX0:%.*]]
+; CHECK-NEXT:    [[GEP1:%.*]] = getelementptr inbounds i8, ptr [[GEP0]], <2 x i64> [[IDX1:%.*]]
+; CHECK-NEXT:    [[GEP2:%.*]] = getelementptr inbounds i8, ptr [[BASE]], <2 x i64> [[IDX2:%.*]]
+; CHECK-NEXT:    [[GEP1_INT:%.*]] = ptrtoint <2 x ptr> [[GEP1]] to <2 x i64>
+; CHECK-NEXT:    [[GEP2_INT:%.*]] = ptrtoint <2 x ptr> [[GEP2]] to <2 x i64>
+; CHECK-NEXT:    [[D:%.*]] = sub <2 x i64> [[GEP2_INT]], [[GEP1_INT]]
+; CHECK-NEXT:    ret <2 x i64> [[D]]
+;
+  %gep0 = getelementptr inbounds i8, ptr %base, i64 %idx0
+  %gep1 = getelementptr inbounds i8, ptr %gep0, <2 x i64> %idx1
+  %gep2 = getelementptr inbounds i8, ptr %base, <2 x i64> %idx2
+  %gep1.int = ptrtoint <2 x ptr> %gep1 to <2 x i64>
+  %gep2.int = ptrtoint <2 x ptr> %gep2 to <2 x i64>
+  %d = sub <2 x i64> %gep2.int, %gep1.int
+  ret <2 x i64> %d
+}