GH-111485: Break up instructions with unused cache entries into component micro-ops (GH-113169)

3 files changed, 27 insertions, 8 deletions

diff --git a/Tools/cases_generator/analyzer.py b/Tools/cases_generator/analyzer.py
index 2147f6f..e077eb0 100644
--- a/Tools/cases_generator/analyzer.py
+++ b/Tools/cases_generator/analyzer.py
@@ -234,9 +234,9 @@ def analyze_stack(op: parser.InstDef) -> StackEffect:
     return StackEffect(inputs, outputs)
 
 
-def analyze_caches(op: parser.InstDef) -> list[CacheEntry]:
+def analyze_caches(inputs: list[parser.InputEffect]) -> list[CacheEntry]:
     caches: list[parser.CacheEffect] = [
-        i for i in op.inputs if isinstance(i, parser.CacheEffect)
+        i for i in inputs if isinstance(i, parser.CacheEffect)
     ]
     return [CacheEntry(i.name, int(i.size)) for i in caches]
 
@@ -314,13 +314,13 @@ def compute_properties(op: parser.InstDef) -> Properties:
     )
 
 
-def make_uop(name: str, op: parser.InstDef) -> Uop:
+def make_uop(name: str, op: parser.InstDef, inputs: list[parser.InputEffect]) -> Uop:
     return Uop(
         name=name,
         context=op.context,
         annotations=op.annotations,
         stack=analyze_stack(op),
-        caches=analyze_caches(op),
+        caches=analyze_caches(inputs),
         body=op.block.tokens,
         properties=compute_properties(op),
     )
@@ -333,7 +333,7 @@ def add_op(op: parser.InstDef, uops: dict[str, Uop]) -> None:
             raise override_error(
                 op.name, op.context, uops[op.name].context, op.tokens[0]
             )
-    uops[op.name] = make_uop(op.name, op)
+    uops[op.name] = make_uop(op.name, op, op.inputs)
 
 
 def add_instruction(
@@ -347,10 +347,27 @@ def desugar_inst(
 ) -> None:
     assert inst.kind == "inst"
     name = inst.name
-    uop = make_uop("_" + inst.name, inst)
+    op_inputs: list[parser.InputEffect] = []
+    parts: list[Part] = []
+    uop_index = -1
+    # Move unused cache entries to the Instruction, removing them from the Uop.
+    for input in inst.inputs:
+        if isinstance(input, parser.CacheEffect) and input.name == "unused":
+            parts.append(Skip(input.size))
+        else:
+            op_inputs.append(input)
+            if uop_index < 0:
+                uop_index = len(parts)
+                # Place holder for the uop.
+                parts.append(Skip(0))
+    uop = make_uop("_" + inst.name, inst, op_inputs)
     uop.implicitly_created = True
     uops[inst.name] = uop
-    add_instruction(name, [uop], instructions)
+    if uop_index < 0:
+        parts.append(uop)
+    else:
+        parts[uop_index] = uop
+    add_instruction(name, parts, instructions)
 
 
 def add_macro(
diff --git a/Tools/cases_generator/parser.py b/Tools/cases_generator/parser.py
index 12173a6..fe4e8e4 100644
--- a/Tools/cases_generator/parser.py
+++ b/Tools/cases_generator/parser.py
@@ -7,6 +7,7 @@ from parsing import (
     Context,
     CacheEffect,
     StackEffect,
+    InputEffect,
     OpName,
     AstNode,
 )
diff --git a/Tools/cases_generator/tier1_generator.py b/Tools/cases_generator/tier1_generator.py
index bcfd2d8..49cede9 100644
--- a/Tools/cases_generator/tier1_generator.py
+++ b/Tools/cases_generator/tier1_generator.py
@@ -151,7 +151,8 @@ def generate_tier1(
         stack = Stack()
         for part in inst.parts:
             # Only emit braces if more than one uop
-            offset = write_uop(part, out, offset, stack, inst, len(inst.parts) > 1)
+            insert_braces = len([p for p in inst.parts if isinstance(p, Uop)]) > 1
+            offset = write_uop(part, out, offset, stack, inst, insert_braces)
         out.start_line()
         if not inst.parts[-1].properties.always_exits:
             stack.flush(out)