[PATCH] D130466: [LICM] - Add option to force thread model single

[Shubham Narlawar via Phabricator via llvm-commits]

gsocshubham added inline comments.


================
Comment at: llvm/test/Transforms/LICM/promote-sink-store-arg.ll:73
+entry:
+  %n.addr = alloca i32, align 4
+  %u.addr = alloca i32, align 4
----------------
gsocshubham wrote:
> This IR is obtained from below C code -
> 
> ```
> void f(int n, int u) {
>     for (int i = 0; i < n; ++i) {
>             u = i;
>     }
> }
> ```
Updated test IR is obtained after running -sroad and -instnamer on -

```
int i, n;

void f(int u[n]) {
    for (i = 0; i < n; ++i) {
          if(u[i])
            u[i] = i;
    }
}
```

Here store to `u` will be not promoted.


================
Comment at: llvm/test/Transforms/LICM/promote-sink-store-capture.ll:83
+entry:
+  %n.addr = alloca i32, align 4
+  %u.addr = alloca i32, align 4
----------------
gsocshubham wrote:
> C testcase which is used to generate below IR -
> 
> ```
> void f(int n, int u) {
>     for (int i = 0, x = u; i < n; ++i) {
>     x = i;
>     }
> }
> ```
> 
> Note - For capture case, store promotion happens irrespective of flag `-licm-force-thread-model-single` i.e. with just `-licm` with current state of LICM. 
> 
> In my last to last revision, without that flag captured store promotion was not happening, maybe some other patches in between have caused it.
Updated test IR is obtained after running -sroad and -instnamer on -

```
int i;

void f(int u) {
    i = 0;
    for (int x = u; i < 20; ++i) {
    x = i;
    }
}
```

Here store to `x` will be promoted.


================
Comment at: llvm/test/Transforms/LICM/promote-sink-store-constant-global.ll:77
+entry:
+  %n.addr = alloca i32, align 4
+  %x = alloca i32, align 4
----------------
gsocshubham wrote:
> This IR is obtained from C testcase -
> 
> ```
> const int u = 7;
> 
> void f(int n) {
>      int x;
>     for (int i = 0; i < n; ++i) {
>         x = u;
>     }
> }
> ```
Updated test IR is obtained after running -sroad and -instnamer on -

```
const int u;

int f(int n) {
     int x, i;
    for (i = 0; i < n; ++i) {
        x = u;
    }
  return x + u;
}
```


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D130466/new/

https://reviews.llvm.org/D130466