From: Reid Kleckner <rnk@google.com>
Date: Thu, 7 Jan 2021 18:21:44 +0000 (-0800)
Subject: Simplify vectorcall argument classification of HVAs, NFC
X-Git-Tag: llvmorg-13-init~1819
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ad55d5c3f32f6598f8ac30b68f4961d82cdb1fed;p=platform%2Fupstream%2Fllvm.git

Simplify vectorcall argument classification of HVAs, NFC

This reduces the number of `WinX86_64ABIInfo::classify` call sites from
3 to 1. The call sites were similar, but passed different values for
FreeSSERegs. Use variables instead of `if`s to manage that argument.
---

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index c6d8942..d36c734 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -1089,11 +1089,6 @@ struct CCState {
   unsigned FreeSSERegs = 0;
 };
 
-enum {
-  // Vectorcall only allows the first 6 parameters to be passed in registers.
-  VectorcallMaxParamNumAsReg = 6
-};
-
 /// X86_32ABIInfo - The X86-32 ABI information.
 class X86_32ABIInfo : public SwiftABIInfo {
   enum Class {
@@ -2405,10 +2400,8 @@ public:
 private:
   ABIArgInfo classify(QualType Ty, unsigned &FreeSSERegs, bool IsReturnType,
                       bool IsVectorCall, bool IsRegCall) const;
-  ABIArgInfo reclassifyHvaArgType(QualType Ty, unsigned &FreeSSERegs,
-                                      const ABIArgInfo &current) const;
-  void computeVectorCallArgs(CGFunctionInfo &FI, unsigned FreeSSERegs,
-                             bool IsVectorCall, bool IsRegCall) const;
+  ABIArgInfo reclassifyHvaArgForVectorCall(QualType Ty, unsigned &FreeSSERegs,
+                                           const ABIArgInfo &current) const;
 
   X86AVXABILevel AVXLevel;
 
@@ -4163,10 +4156,8 @@ Address X86_64ABIInfo::EmitMSVAArg(CodeGenFunction &CGF, Address VAListAddr,
                           /*allowHigherAlign*/ false);
 }
 
-ABIArgInfo
-WinX86_64ABIInfo::reclassifyHvaArgType(QualType Ty, unsigned &FreeSSERegs,
-                                    const ABIArgInfo &current) const {
-  // Assumes vectorCall calling convention.
+ABIArgInfo WinX86_64ABIInfo::reclassifyHvaArgForVectorCall(
+    QualType Ty, unsigned &FreeSSERegs, const ABIArgInfo &current) const {
   const Type *Base = nullptr;
   uint64_t NumElts = 0;
 
@@ -4299,31 +4290,6 @@ ABIArgInfo WinX86_64ABIInfo::classify(QualType Ty, unsigned &FreeSSERegs,
   return ABIArgInfo::getDirect();
 }
 
-void WinX86_64ABIInfo::computeVectorCallArgs(CGFunctionInfo &FI,
-                                             unsigned FreeSSERegs,
-                                             bool IsVectorCall,
-                                             bool IsRegCall) const {
-  unsigned Count = 0;
-  for (auto &I : FI.arguments()) {
-    // Vectorcall in x64 only permits the first 6 arguments to be passed
-    // as XMM/YMM registers.
-    if (Count < VectorcallMaxParamNumAsReg)
-      I.info = classify(I.type, FreeSSERegs, false, IsVectorCall, IsRegCall);
-    else {
-      // Since these cannot be passed in registers, pretend no registers
-      // are left.
-      unsigned ZeroSSERegsAvail = 0;
-      I.info = classify(I.type, /*FreeSSERegs=*/ZeroSSERegsAvail, false,
-                        IsVectorCall, IsRegCall);
-    }
-    ++Count;
-  }
-
-  for (auto &I : FI.arguments()) {
-    I.info = reclassifyHvaArgType(I.type, FreeSSERegs, I.info);
-  }
-}
-
 void WinX86_64ABIInfo::computeInfo(CGFunctionInfo &FI) const {
   const unsigned CC = FI.getCallingConvention();
   bool IsVectorCall = CC == llvm::CallingConv::X86_VectorCall;
@@ -4358,13 +4324,25 @@ void WinX86_64ABIInfo::computeInfo(CGFunctionInfo &FI) const {
     FreeSSERegs = 16;
   }
 
+  unsigned ArgNum = 0;
+  unsigned ZeroSSERegs = 0;
+  for (auto &I : FI.arguments()) {
+    // Vectorcall in x64 only permits the first 6 arguments to be passed as
+    // XMM/YMM registers. After the sixth argument, pretend no vector
+    // registers are left.
+    unsigned *MaybeFreeSSERegs =
+        (IsVectorCall && ArgNum >= 6) ? &ZeroSSERegs : &FreeSSERegs;
+    I.info =
+        classify(I.type, *MaybeFreeSSERegs, false, IsVectorCall, IsRegCall);
+    ++ArgNum;
+  }
+
   if (IsVectorCall) {
-    computeVectorCallArgs(FI, FreeSSERegs, IsVectorCall, IsRegCall);
-  } else {
+    // For vectorcall, assign aggregate HVAs to any free vector registers in a
+    // second pass.
     for (auto &I : FI.arguments())
-      I.info = classify(I.type, FreeSSERegs, false, IsVectorCall, IsRegCall);
+      I.info = reclassifyHvaArgForVectorCall(I.type, FreeSSERegs, I.info);
   }
-
 }
 
 Address WinX86_64ABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,