gh-138250: load fast optimization should fall through to empty blocks (#138249)

DinoV · web-flow · commit e05182f98ea1 · 2025-08-29T11:49:35.000-07:00
load fast optimization should fall through to empty blocks
diff --git a/Python/flowgraph.c b/Python/flowgraph.c
@@ -2993,11 +2993,8 @@ optimize_load_fast(cfg_builder *g)
         }
 
         // Push fallthrough block
-        cfg_instr *term = basicblock_last_instr(block);
-        if (term != NULL && block->b_next != NULL &&
-            !(IS_UNCONDITIONAL_JUMP_OPCODE(term->i_opcode) ||
-              IS_SCOPE_EXIT_OPCODE(term->i_opcode))) {
-            assert(BB_HAS_FALLTHROUGH(block));
+        if (BB_HAS_FALLTHROUGH(block)) {
+            assert(block->b_next != NULL);
             load_fast_push_block(&sp, block->b_next, refs.size);
         }
 

Original file line number	Diff line number	Diff line change
`@@ -2993,11 +2993,8 @@ optimize_load_fast(cfg_builder *g)`
`2993`	`2993`	`}`
`2994`	`2994`
`2995`	`2995`	`// Push fallthrough block`
`2996`		`- cfg_instr *term = basicblock_last_instr(block);`
`2997`		`- if (term != NULL && block->b_next != NULL &&`
`2998`		`- !(IS_UNCONDITIONAL_JUMP_OPCODE(term->i_opcode) \|\|`
`2999`		`- IS_SCOPE_EXIT_OPCODE(term->i_opcode))) {`
`3000`		`- assert(BB_HAS_FALLTHROUGH(block));`
	`2996`	`+ if (BB_HAS_FALLTHROUGH(block)) {`
	`2997`	`+ assert(block->b_next != NULL);`
`3001`	`2998`	`load_fast_push_block(&sp, block->b_next, refs.size);`
`3002`	`2999`	`}`
`3003`	`3000`