Remove unnecessary Load and Store pair (#8433)

This commit removes unnecessary Load and Store pairs in IR.

When the IR is like
```
let %1 = var
let %2 = load(%ptr)
store(%1 %2)
```
This PR will replace all uses of %1 with %ptr.
And the load and store instructions will be removed.

But I found that there can be cases where %2 might be still used later
in other IRs.
For these cases, the removal of load instruction relies on DCE.

---------

Co-authored-by: slangbot <ellieh+slangbot@nvidia.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/tests/metal/vector-get-element-ptr.slang b/tests/metal/vector-get-element-ptr.slang
index af2acabbc..1c616b37e 100644
--- a/tests/metal/vector-get-element-ptr.slang
+++ b/tests/metal/vector-get-element-ptr.slang
@@ -14,11 +14,11 @@ void modify(inout int v)
 void computeMain(int3 v : SV_DispatchThreadID)
 {
     int3 u = v;
-    // CHECK: int [[TEMP:[a-zA-Z0-9_]+]] = u{{.*}}.x;
+    // CHECK: int [[TEMP:[a-zA-Z0-9_]+]] = [[OUT:[a-zA-Z0-9_]+]].x;
     // CHECK: modify{{.*}}(&[[TEMP]])
-    // CHECK: u{{.*}}.x = [[TEMP]];
+    // CHECK: [[OUT]].x = [[TEMP]];
 
     modify(u.x);
     // BUF: 2
     outputBuffer[0] = u.x + u.y;
-}
\ No newline at end of file
+}