R600: Fix R600ControlFlowFinalizer not considering VTX_READ 128 bit dst reg

Patch by: Vincent Lejeune

https://bugs.freedesktop.org/show_bug.cgi?id=64877

NOTE: This is a candidate for the 3.3 branch.


Merged from r182600
Author: Tom Stellard <[email protected]>
Date:   Thu May 23 18:26:42 2013 +0000

git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_33@185868 91177308-0d34-0410-b5e6-96231b3b80d8

Author: tstellarAMD

lib/Target/R600/R600ControlFlowFinalizer.cpp

@@ -116,8 +116,15 @@ class R600ControlFlowFinalizer : public MachineFunctionPass {
       const MachineOperand &MO = *I;
       if (!MO.isReg())
         continue;
-      if (MO.isDef())
-        DstMI = MO.getReg();
+      if (MO.isDef()) {
+        unsigned Reg = MO.getReg();
+        if (AMDGPU::R600_Reg128RegClass.contains(Reg))
+          DstMI = Reg;
+        else
+          DstMI = TRI.getMatchingSuperReg(Reg,
+              TRI.getSubRegFromChannel(TRI.getHWRegChan(Reg)),
+              &AMDGPU::R600_Reg128RegClass);
+      }
       if (MO.isUse()) {
         unsigned Reg = MO.getReg();
         if (AMDGPU::R600_Reg128RegClass.contains(Reg))

test/CodeGen/R600/vtx-schedule.ll

@@ -0,0 +1,22 @@
+; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
+
+; This test is for a scheduler bug where VTX_READ instructions that used
+; the result of another VTX_READ instruction were being grouped in the
+; same fetch clasue.
+
+; CHECK: @test
+; CHECK: Fetch clause
+; CHECK_VTX_READ_32 [[IN0:T[0-9]+\.X]], [[IN0]], 40
+; CHECK_VTX_READ_32 [[IN1:T[0-9]+\.X]], [[IN1]], 44
+; CHECK: Fetch clause
+; CHECK_VTX_READ_32 [[IN0:T[0-9]+\.X]], [[IN0]], 0
+; CHECK_VTX_READ_32 [[IN1:T[0-9]+\.X]], [[IN1]], 0
+define void @test(i32 addrspace(1)* nocapture %out, i32 addrspace(1)* nocapture %in0, i32 addrspace(1)* nocapture %in1) {
+entry:
+  %0 = load i32 addrspace(1)* %in0, align 4
+  %1 = load i32 addrspace(1)* %in1, align 4
+  %cmp.i = icmp slt i32 %0, %1
+  %cond.i = select i1 %cmp.i, i32 %0, i32 %1
+  store i32 %cond.i, i32 addrspace(1)* %out, align 4
+  ret void
+}