[llvm] Account for inline assembly instructions in inlining cost. (PR #146628)

[Kazu Hirata via llvm-commits]

================
@@ -777,6 +786,42 @@ class InlineCostCallAnalyzer final : public CallAnalyzer {
 
     addCost(SwitchCost);
   }
+
+  // Parses the inline assembly argument to account for its cost. Inline
+  // assembly instructions incur higher costs for inlining since they cannot be
+  // analyzed and optimized.
+  void onInlineAsm(InlineAsm &Arg) override {
+    SmallVector<StringRef, 4> Fragments;
+    Arg.getAsmString().split(Fragments, "\n");
+    int SectionLevel = 0;
+    int InlineAsmInstrCount = 0;
+    for (const auto &Fragment : Fragments) {
+      // Trim whitespaces and comments.
+      auto Trimmed = Fragment.trim();
+      size_t hashPos = Trimmed.find('#');
+      if (hashPos != StringRef::npos)
+        Trimmed = Trimmed.substr(0, hashPos);
----------------
kazutakahirata wrote:

May I suggest something like this, mainly because it's shorter?  Note that this has slightly different semantics than your original code.  With your original code, whitespace between the inline assembly instruction and `#` is preserved.  With my suggestion, such whitespace is trimmed.

```suggestion
      auto Trimmed = Fragment.split('#').first.trim();
```


https://github.com/llvm/llvm-project/pull/146628