[Mlir-commits] [mlir] 24a37a3 - [MLIR] add entry block to MLIR grammar.

[llvmlistbot at llvm.org]

Author: Siddharth Bhat
Date: 2022-02-17T15:40:43+05:30
New Revision: 24a37a396a9bd6b73b05b4eafce8b87e7a748cf9

URL: https://github.com/llvm/llvm-project/commit/24a37a396a9bd6b73b05b4eafce8b87e7a748cf9
DIFF: https://github.com/llvm/llvm-project/commit/24a37a396a9bd6b73b05b4eafce8b87e7a748cf9.diff

LOG: [MLIR] add entry block to MLIR grammar.

The MLIR parser allows regions to have an unnamed entry block.
Make this explicit in the language grammar.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D119950

Added: 
    

Modified: 
    mlir/docs/LangRef.md

Removed: 
    


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diff  --git a/mlir/docs/LangRef.md b/mlir/docs/LangRef.md
index 92a5413a656d8..2fe1c6248c8a4 100644
--- a/mlir/docs/LangRef.md
+++ b/mlir/docs/LangRef.md
@@ -443,7 +443,8 @@ entry block cannot be listed as a successor of any other block. The syntax for a
 region is as follows:
 
 ```
-region ::= `{` block* `}`
+region      ::= `{` entry-block? block* `}`
+entry-block ::= operation+
 ```
 
 A function body is an example of a region: it consists of a CFG of blocks and
@@ -454,6 +455,11 @@ arguments must match the result types of the function signature. Similarly, the
 function arguments must match the types and count of the region arguments. In
 general, operations with regions can define these correspondences arbitrarily.
 
+An *entry block* is a block with no label and no arguments that may occur at
+the beginning of a region. It enables a common pattern of using a region to
+open a new scope.
+
+
 ### Value Scoping
 
 Regions provide hierarchical encapsulation of programs: it is impossible to