[llvm] [clang] [clang-tools-extra] [ISel] Add pattern matching for depositing subreg value (PR #75978)

[Shengchen Kan via cfe-commits]

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@@ -1515,6 +1515,15 @@ def : Pat<(X86add_flag_nocf GR32:$src1, 128),
 def : Pat<(X86add_flag_nocf GR64:$src1, 128),
           (SUB64ri32 GR64:$src1, -128)>;
 
+// Depositing value to 8/16 bit subreg:
+def : Pat<(or (and GR64:$dst, -256), 
+              (i64 (zextloadi8 addr:$src))),
+      (INSERT_SUBREG (i64 (COPY $dst)), (MOV8rm  i8mem:$src), sub_8bit)>; 
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KanRobert wrote:

align with `(or`

https://github.com/llvm/llvm-project/pull/75978