From: Chris Lattner <sabre@nondot.org>
Date: Mon, 9 Apr 2007 05:49:22 +0000 (+0000)
Subject: move a bunch of register constraints from being handled by
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=0f65cad57f041a2e7d3e6e11809a795c13cbfec7;p=oota-llvm.git

move a bunch of register constraints from being handled by
getRegClassForInlineAsmConstraint to being handled by
getRegForInlineAsmConstraint.  This allows us to let the llvm register allocator
allocate, which gives us better code.  For example, X86/2007-01-29-InlineAsm-ir.ll
used to compile to:

_run_init_process:
        subl $4, %esp
        movl %ebx, (%esp)
        xorl %ebx, %ebx
        movl $11, %eax
        movl %ebx, %ecx
        movl %ebx, %edx
        # InlineAsm Start
        push %ebx ; movl %ebx,%ebx ; int $0x80 ; pop %ebx
        # InlineAsm End

Now we get:
_run_init_process:
        xorl %ecx, %ecx
        movl $11, %eax
        movl %ecx, %edx
        # InlineAsm Start
        push %ebx ; movl %ecx,%ebx ; int $0x80 ; pop %ebx
        # InlineAsm End


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35804 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 20d259e8265..18c5b32a041 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -4645,39 +4645,12 @@ getRegClassForInlineAsmConstraint(const std::string &Constraint,
                                   MVT::ValueType VT) const {
   if (Constraint.size() == 1) {
     // FIXME: not handling fp-stack yet!
-    // FIXME: not handling MMX registers yet ('y' constraint).
     switch (Constraint[0]) {      // GCC X86 Constraint Letters
     default: break;  // Unknown constraint letter
     case 'A':   // EAX/EDX
       if (VT == MVT::i32 || VT == MVT::i64)
         return make_vector<unsigned>(X86::EAX, X86::EDX, 0);
       break;
-    case 'r':   // GENERAL_REGS
-    case 'R':   // LEGACY_REGS
-      if (VT == MVT::i64 && Subtarget->is64Bit())
-        return make_vector<unsigned>(X86::RAX, X86::RDX, X86::RCX, X86::RBX,
-                                     X86::RSI, X86::RDI, X86::RBP, X86::RSP,
-                                     X86::R8,  X86::R9,  X86::R10, X86::R11,
-                                     X86::R12, X86::R13, X86::R14, X86::R15, 0);
-      if (VT == MVT::i32)
-        return make_vector<unsigned>(X86::EAX, X86::EDX, X86::ECX, X86::EBX,
-                                     X86::ESI, X86::EDI, X86::EBP, X86::ESP, 0);
-      else if (VT == MVT::i16)
-        return make_vector<unsigned>(X86::AX, X86::DX, X86::CX, X86::BX,
-                                     X86::SI, X86::DI, X86::BP, X86::SP, 0);
-      else if (VT == MVT::i8)
-        return make_vector<unsigned>(X86::AL, X86::DL, X86::CL, X86::BL, 0);
-      break;
-    case 'l':   // INDEX_REGS
-      if (VT == MVT::i32)
-        return make_vector<unsigned>(X86::EAX, X86::EDX, X86::ECX, X86::EBX,
-                                     X86::ESI, X86::EDI, X86::EBP, 0);
-      else if (VT == MVT::i16)
-        return make_vector<unsigned>(X86::AX, X86::DX, X86::CX, X86::BX,
-                                     X86::SI, X86::DI, X86::BP, 0);
-      else if (VT == MVT::i8)
-        return make_vector<unsigned>(X86::AL, X86::DL, X86::CL, X86::DL, 0);
-      break;
     case 'q':   // Q_REGS (GENERAL_REGS in 64-bit mode)
     case 'Q':   // Q_REGS
       if (VT == MVT::i32)
@@ -4687,18 +4660,6 @@ getRegClassForInlineAsmConstraint(const std::string &Constraint,
       else if (VT == MVT::i8)
         return make_vector<unsigned>(X86::AL, X86::DL, X86::CL, X86::DL, 0);
         break;
-    case 'x':   // SSE_REGS if SSE1 allowed
-      if (Subtarget->hasSSE1())
-        return make_vector<unsigned>(X86::XMM0, X86::XMM1, X86::XMM2, X86::XMM3,
-                                     X86::XMM4, X86::XMM5, X86::XMM6, X86::XMM7,
-                                     0);
-      return std::vector<unsigned>();
-    case 'Y':   // SSE_REGS if SSE2 allowed
-      if (Subtarget->hasSSE2())
-        return make_vector<unsigned>(X86::XMM0, X86::XMM1, X86::XMM2, X86::XMM3,
-                                     X86::XMM4, X86::XMM5, X86::XMM6, X86::XMM7,
-                                     0);
-      return std::vector<unsigned>();
     }
   }
 
@@ -4714,11 +4675,44 @@ X86TargetLowering::getRegForInlineAsmConstraint(const std::string &Constraint,
     // GCC Constraint Letters
     switch (Constraint[0]) {
     default: break;
-    case 'x': 
-      if (VT == MVT::f32 || VT == MVT::i32)
+    case 'r':   // GENERAL_REGS
+    case 'R':   // LEGACY_REGS
+    case 'l':   // INDEX_REGS
+      if (VT == MVT::i64 && Subtarget->is64Bit())
+        return std::make_pair(0U, X86::GR64RegisterClass);
+      if (VT == MVT::i32)
+        return std::make_pair(0U, X86::GR32RegisterClass);
+      else if (VT == MVT::i16)
+        return std::make_pair(0U, X86::GR16RegisterClass);
+      else if (VT == MVT::i8)
+        return std::make_pair(0U, X86::GR8RegisterClass);
+      break;
+    // FIXME: not handling MMX registers yet ('y' constraint).
+    case 'Y':   // SSE_REGS if SSE2 allowed
+      if (!Subtarget->hasSSE2()) break;
+      // FALL THROUGH.
+    case 'x':   // SSE_REGS if SSE1 allowed
+      if (!Subtarget->hasSSE1()) break;
+      
+      switch (VT) {
+      default: break;
+      // Scalar SSE types.
+      case MVT::f32:
+      case MVT::i32:
         return std::make_pair(0U, X86::FR32RegisterClass);
-      if (VT == MVT::f64 || VT == MVT::i64)
+      case MVT::f64:
+      case MVT::i64:
         return std::make_pair(0U, X86::FR64RegisterClass);
+      // Vector types.
+      case MVT::Vector:
+      case MVT::v16i8:
+      case MVT::v8i16:
+      case MVT::v4i32:
+      case MVT::v2i64:
+      case MVT::v4f32:
+      case MVT::v2f64:
+        return std::make_pair(0U, X86::VR128RegisterClass);
+      }
       break;
     }
   }