[llvm] [GlobalISel] Document minimum legality requirements for G_IMPLICIT_DEF. (PR #117609)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-globalisel

Author: Amara Emerson (aemerson)

<details>
<summary>Changes</summary>

So that @<!-- -->tschuett can fix up #<!-- -->117439

---
Full diff: https://github.com/llvm/llvm-project/pull/117609.diff


1 Files Affected:

- (modified) llvm/docs/GlobalISel/Legalizer.rst (+2-2) 


``````````diff
diff --git a/llvm/docs/GlobalISel/Legalizer.rst b/llvm/docs/GlobalISel/Legalizer.rst
index 1ff7b304b3a013..cd27a0249c4b3e 100644
--- a/llvm/docs/GlobalISel/Legalizer.rst
+++ b/llvm/docs/GlobalISel/Legalizer.rst
@@ -338,8 +338,8 @@ G_BUILD_VECTOR_TRUNC, G_CONCAT_VECTORS, G_UNMERGE_VALUES, G_PTRTOINT, and
 G_INTTOPTR have already been noted above. In addition to those, the following
 operations have requirements:
 
-* At least one G_IMPLICIT_DEF must be legal. This is usually trivial as it
-  requires no code to be selected.
+* For every type that can be produced by any instruction, G_IMPLICIT_DEF must be
+  legal. This is usually trivial as it requires no code to be selected.
 * G_PHI must be legal for all types in the producer and consumer typesets. This
   is usually trivial as it requires no code to be selected.
 * At least one G_FRAME_INDEX must be legal

``````````

</details>


https://github.com/llvm/llvm-project/pull/117609