[PATCH] D120329: [SelectionDAG] Emit calls to __divei4 and friends for division/remainder of large integers

[LuoYuanke via Phabricator via llvm-commits]

LuoYuanke added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:3921
+           "Unexpected argument type for lowering");
+    SDValue StackPtr = DAG.CreateStackTemporary(ArgVT, 4);
+    Entry.Node = StackPtr;
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Just be curious. Why the alignment is 4 for all target?


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Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:3925
+    Type *ArgTy = ArgVT.getTypeForEVT(*DAG.getContext());
+    Entry.Ty = PointerType::get(ArgTy, 0);
+    Entry.IsSExt = false;
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Not sure if the pointer is "i32 *" or "i129 *".


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Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:3950
+                    std::move(Args))
+      .setInRegister()
+      .setSExtResult(/*isSigned*/ false)
----------------
Will the parameter passed in register for i386?


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Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:3952
+      .setSExtResult(/*isSigned*/ false)
+      .setZExtResult(/*!isSigned*/ true);
+
----------------
Given the return value is void, why set the S/ZExt?


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Comment at: llvm/test/CodeGen/X86/udivmodei5.ll:2
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown | FileCheck %s
+
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Generate case for i386?


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Comment at: llvm/test/CodeGen/X86/udivmodei5.ll:28
+; CHECK-NEXT:    movq {{[0-9]+}}(%rsp), %rax
+; CHECK-NEXT:    movq {{[0-9]+}}(%rsp), %rdx
+; CHECK-NEXT:    addq $104, %rsp
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Is there any ABI description that shows how to pass i129 parameter or return i129 value?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D120329/new/

https://reviews.llvm.org/D120329