[InstSimplify] Clean up naming in ptr diff test (NFC)

Turns out there already was a test for the non-inbounds variant,
so remove the duplicate. Rename the tests to be more meaningful.
Drop irrelevant target triple.

Author: nikic

llvm/test/Transforms/InstSimplify/ptr_diff.ll

@@ -1,10 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -passes=instsimplify -S | FileCheck %s
-target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
-target triple = "x86_64-unknown-linux-gnu"
 
-define i64 @ptrdiff1(ptr %ptr) {
-; CHECK-LABEL: @ptrdiff1(
+define i64 @ptrdiff(ptr %ptr) {
+; CHECK-LABEL: @ptrdiff(
 ; CHECK-NEXT:    ret i64 42
 ;
   %last = getelementptr inbounds i8, ptr %ptr, i32 42
@@ -29,8 +27,8 @@ define i64 @ptrdiff_no_inbounds(ptr %ptr) {
   ret i64 %diff
 }
 
-define i64 @ptrdiff2(ptr %ptr) {
-; CHECK-LABEL: @ptrdiff2(
+define i64 @ptrdiff_chain(ptr %ptr) {
+; CHECK-LABEL: @ptrdiff_chain(
 ; CHECK-NEXT:    ret i64 42
 ;
   %first2 = getelementptr inbounds i8, ptr %ptr, i32 1
@@ -46,25 +44,9 @@ define i64 @ptrdiff2(ptr %ptr) {
   ret i64 %diff
 }
 
-define i64 @ptrdiff3(ptr %ptr) {
-; Don't bother with non-inbounds GEPs.
-; CHECK-LABEL: @ptrdiff3(
-; CHECK-NEXT:    [[LAST1:%.*]] = getelementptr i8, ptr [[LAST:%.*]], i32 42
-; CHECK-NEXT:    [[LAST_INT:%.*]] = ptrtoint ptr [[LAST]] to i64
-; CHECK-NEXT:    [[LAST_INT1:%.*]] = ptrtoint ptr [[LAST1]] to i64
-; CHECK-NEXT:    [[DIFF:%.*]] = sub i64 [[LAST_INT1]], [[LAST_INT]]
-; CHECK-NEXT:    ret i64 [[DIFF]]
-;
-  %last = getelementptr i8, ptr %ptr, i32 42
-  %first.int = ptrtoint ptr %ptr to i64
-  %last.int = ptrtoint ptr %last to i64
-  %diff = sub i64 %last.int, %first.int
-  ret i64 %diff
-}
-
-define <4 x i32> @ptrdiff4(<4 x ptr> %arg) nounwind {
 ; Handle simple cases of vectors of pointers.
-; CHECK-LABEL: @ptrdiff4(
+define <4 x i32> @ptrdiff_vectors(<4 x ptr> %arg) nounwind {
+; CHECK-LABEL: @ptrdiff_vectors(
 ; CHECK-NEXT:    ret <4 x i32> zeroinitializer
 ;
   %p1 = ptrtoint <4 x ptr> %arg to <4 x i32>
@@ -78,8 +60,8 @@ define <4 x i32> @ptrdiff4(<4 x ptr> %arg) nounwind {
 
 @global = internal global %struct.ham zeroinitializer, align 4
 
-define i32 @ptrdiff5() nounwind {
-; CHECK-LABEL: @ptrdiff5(
+define i32 @ptrdiff_global() nounwind {
+; CHECK-LABEL: @ptrdiff_global(
 ; CHECK-NEXT:  bb:
 ; CHECK-NEXT:    ret i32 0
 ;