[PATCH] D88487: [TableGen][GlobalISel] add handling of nested *_SUBREG

[Gabriel Hjort Åkerlund via Phabricator via llvm-commits]

ehjogab created this revision.
ehjogab added reviewers: dsanders, arsenm, qcolombet, ab, bjope.
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When nesting INSERT_SUBREG and EXTRACT_SUBREG, GlobalISelEmitter would
fail to find the register class of the nested node. This patch fixes
that for registers with subregs.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D88487

Files:
  llvm/test/TableGen/GlobalISelEmitter-nested-subregs.td
  llvm/utils/TableGen/GlobalISelEmitter.cpp


Index: llvm/utils/TableGen/GlobalISelEmitter.cpp
===================================================================
--- llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -4951,6 +4951,17 @@
       return None;
     return getRegClassFromLeaf(RCChild);
   }
+  else if (InstName == "INSERT_SUBREG") {
+    TreePatternNode *Child0 = N->getChild(0);
+    assert(Child0->getNumTypes() == 1 && "Unexpected number of types!");
+    const TypeSetByHwMode &VTy = Child0->getExtType(0);
+    return inferSuperRegisterClassForNode(VTy, Child0, N->getChild(2));
+  }
+  else if (InstName == "EXTRACT_SUBREG") {
+    assert(N->getNumTypes() == 1 && "Unexpected number of types!");
+    const TypeSetByHwMode &VTy = N->getExtType(0);
+    return inferSuperRegisterClass(VTy, N->getChild(1));
+  }
 
   // Handle destination record types that we can safely infer a register class
   // from.
Index: llvm/test/TableGen/GlobalISelEmitter-nested-subregs.td
===================================================================
--- /dev/null
+++ llvm/test/TableGen/GlobalISelEmitter-nested-subregs.td
@@ -0,0 +1,39 @@
+// RUN: llvm-tblgen %s -gen-global-isel -optimize-match-table=false -I %p/../../include -I %p/Common -o - | FileCheck %s
+
+include "llvm/Target/Target.td"
+include "GlobalISelEmitterCommon.td"
+
+let Namespace = "MyTarget" in {
+
+def lo8  : SubRegIndex<8>;
+def hi8  : SubRegIndex<8, 8>;
+def lo16 : SubRegIndex<16>;
+def hi16 : SubRegIndex<16, 16>;
+
+def a0bl : Register<"a0bl">;
+def a0bh : Register<"a0bh">;
+def a0wh : Register<"a0wh">;
+
+} // Namespace = "MyTarget"
+
+def a0wl: RegisterWithSubRegs<"a0", [a0bh, a0bl]> {
+  let SubRegIndices = [hi8, lo8];
+  let CoveredBySubRegs = 1;
+}
+
+def a0: RegisterWithSubRegs<"a0", [a0wh, a0wl]> {
+  let SubRegIndices = [hi16, lo16];
+  let CoveredBySubRegs = 1;
+}
+
+def A0b : RegisterClass<"MyTarget",  [i8],  8, (add a0bl)>;
+def A0w : RegisterClass<"MyTarget", [i16], 16, (add a0wl)>;
+def A0  : RegisterClass<"MyTarget", [i32], 32, (add a0)>;
+
+def : Pat<(i16 (anyext i8:$src)),
+          (i16 (EXTRACT_SUBREG
+                 (i32 (INSERT_SUBREG
+                        (i32 (IMPLICIT_DEF)),
+                        A0b:$src,
+                        lo8)),
+                 lo16))>;


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