From 7cbeb2431c7264d0848d1343f43914f970828ac7 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 21 Feb 2008 04:55:52 +0000
Subject: [PATCH] Fix a (harmless) but where vregs were added to the used reg
 lists for inline asms.

Fix PR2078 by marking aliases of registers used when a register is
marked used.  This prevents EAX from being allocated when AX is listed
in the clobber set for the asm.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47426 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 35 ++++++++++++++-----
 .../X86/2008-02-20-InlineAsmClobber.ll        | 15 ++++++++
 2 files changed, 41 insertions(+), 9 deletions(-)
 create mode 100644 test/CodeGen/X86/2008-02-20-InlineAsmClobber.ll

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index b5e39a11d31..f36a12078c3 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -3347,12 +3347,29 @@ struct AsmOperandInfo : public InlineAsm::ConstraintInfo {
   /// busy in OutputRegs/InputRegs.
   void MarkAllocatedRegs(bool isOutReg, bool isInReg,
                          std::set<unsigned> &OutputRegs, 
-                         std::set<unsigned> &InputRegs) const {
-     if (isOutReg)
-       OutputRegs.insert(AssignedRegs.Regs.begin(), AssignedRegs.Regs.end());
-     if (isInReg)
-       InputRegs.insert(AssignedRegs.Regs.begin(), AssignedRegs.Regs.end());
-   }
+                         std::set<unsigned> &InputRegs,
+                         const TargetRegisterInfo &TRI) const {
+    if (isOutReg) {
+      for (unsigned i = 0, e = AssignedRegs.Regs.size(); i != e; ++i)
+        MarkRegAndAliases(AssignedRegs.Regs[i], OutputRegs, TRI);
+    }
+    if (isInReg) {
+      for (unsigned i = 0, e = AssignedRegs.Regs.size(); i != e; ++i)
+        MarkRegAndAliases(AssignedRegs.Regs[i], InputRegs, TRI);
+    }
+  }
+  
+private:
+  /// MarkRegAndAliases - Mark the specified register and all aliases in the
+  /// specified set.
+  static void MarkRegAndAliases(unsigned Reg, std::set<unsigned> &Regs, 
+                                const TargetRegisterInfo &TRI) {
+    assert(TargetRegisterInfo::isPhysicalRegister(Reg) && "Isn't a physreg");
+    Regs.insert(Reg);
+    if (const unsigned *Aliases = TRI.getAliasSet(Reg))
+      for (; *Aliases; ++Aliases)
+        Regs.insert(*Aliases);
+  }
 };
 } // end anon namespace.
 
@@ -3491,7 +3508,8 @@ GetRegistersForValue(AsmOperandInfo &OpInfo, bool HasEarlyClobber,
       }
     }
     OpInfo.AssignedRegs = RegsForValue(Regs, RegVT, ValueVT);
-    OpInfo.MarkAllocatedRegs(isOutReg, isInReg, OutputRegs, InputRegs);
+    const TargetRegisterInfo *TRI = DAG.getTarget().getRegisterInfo();
+    OpInfo.MarkAllocatedRegs(isOutReg, isInReg, OutputRegs, InputRegs, *TRI);
     return;
   }
   
@@ -3519,7 +3537,6 @@ GetRegistersForValue(AsmOperandInfo &OpInfo, bool HasEarlyClobber,
         Regs.push_back(RegInfo.createVirtualRegister(PhysReg.second));
       
       OpInfo.AssignedRegs = RegsForValue(Regs, RegVT, ValueVT);
-      OpInfo.MarkAllocatedRegs(isOutReg, isInReg, OutputRegs, InputRegs);
       return;
     }
     
@@ -3571,7 +3588,7 @@ GetRegistersForValue(AsmOperandInfo &OpInfo, bool HasEarlyClobber,
       
       OpInfo.AssignedRegs = RegsForValue(Regs, *RC->vt_begin(), 
                                          OpInfo.ConstraintVT);
-      OpInfo.MarkAllocatedRegs(isOutReg, isInReg, OutputRegs, InputRegs);
+      OpInfo.MarkAllocatedRegs(isOutReg, isInReg, OutputRegs, InputRegs, *TRI);
       return;
     }
   }
diff --git a/test/CodeGen/X86/2008-02-20-InlineAsmClobber.ll b/test/CodeGen/X86/2008-02-20-InlineAsmClobber.ll
new file mode 100644
index 00000000000..94f4e18250a
--- /dev/null
+++ b/test/CodeGen/X86/2008-02-20-InlineAsmClobber.ll
@@ -0,0 +1,15 @@
+; RUN: llvm-as < %s | llc | grep {%ecx %ecx}
+; PR2078
+; The clobber list says that "ax" is clobbered.  Make sure that eax isn't 
+; allocated to the input/output register.
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i386-apple-darwin8"
+@pixels = weak global i32 0		; <i32*> [#uses=2]
+
+define void @test() nounwind  {
+entry:
+	%tmp = load i32* @pixels, align 4		; <i32> [#uses=1]
+	%tmp1 = tail call i32 asm sideeffect "$0 $1", "=r,0,~{dirflag},~{fpsr},~{flags},~{ax}"( i32 %tmp ) nounwind 		; <i32> [#uses=1]
+	store i32 %tmp1, i32* @pixels, align 4
+	ret void
+}
-- 
2.34.1