R600/SI: Use VSrc_* register classes as the default classes for types

Since the VSrc_* register classes contain both VGPRs and SGPRs, copies
that used be emitted by isel like this:

SGPR = COPY VGPR

Will now be emitted like this:

VSrC = COPY VGPR

This patch also adds a pass that tries to identify and fix situations where
a VGPR to SGPR copy may occur.  Hopefully, these changes will make it
impossible for the compiler to generate illegal VGPR to SGPR copies.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187831 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 84 insertions, 0 deletions

diff --git a/test/CodeGen/R600/sgpr-copy.ll b/test/CodeGen/R600/sgpr-copy.ll
new file mode 100644
index 0000000000..b0d4549300
--- /dev/null
+++ b/test/CodeGen/R600/sgpr-copy.ll
@@ -0,0 +1,84 @@
+; RUN: llc < %s -march=r600 -mcpu=SI | FileCheck %s
+
+; This test checks that no VGPR to SGPR copies are created by the register
+; allocator.
+; CHECK: @main
+; CHECK: S_BUFFER_LOAD_DWORD [[DST:SGPR[0-9]]], {{[SGPR_[0-9]+}}, 0
+; CHECK: V_MOV_B32_e32 VGPR{{[0-9]}}, [[DST]]
+
+define void @main(<16 x i8> addrspace(2)* inreg, <16 x i8> addrspace(2)* inreg, <32 x i8> addrspace(2)* inreg, i32 inreg, <2 x i32>, <2 x i32>, <2 x i32>, <3 x i32>, <2 x i32>, <2 x i32>, <2 x i32>, float, float, float, float, float, float, float, float, float) #0 {
+main_body:
+  %20 = getelementptr <16 x i8> addrspace(2)* %0, i32 0
+  %21 = load <16 x i8> addrspace(2)* %20, !tbaa !0
+  %22 = call float @llvm.SI.load.const(<16 x i8> %21, i32 0)
+  %23 = call float @llvm.SI.load.const(<16 x i8> %21, i32 16)
+  %24 = call float @llvm.SI.load.const(<16 x i8> %21, i32 32)
+  %25 = fptosi float %23 to i32
+  %26 = icmp ne i32 %25, 0
+  br i1 %26, label %ENDIF, label %ELSE
+
+ELSE:                                             ; preds = %main_body
+  %27 = fsub float -0.000000e+00, %22
+  br label %ENDIF
+
+ENDIF:                                            ; preds = %main_body, %ELSE
+  %temp.0 = phi float [ %27, %ELSE ], [ %22, %main_body ]
+  %28 = fadd float %temp.0, %24
+  call void @llvm.SI.export(i32 15, i32 1, i32 1, i32 0, i32 0, float %28, float %28, float 0.000000e+00, float 1.000000e+00)
+  ret void
+}
+
+; We just want ot make sure the program doesn't crash
+; CHECK: @loop
+
+define void @loop(<16 x i8> addrspace(2)* inreg, <16 x i8> addrspace(2)* inreg, <32 x i8> addrspace(2)* inreg, i32 inreg, <2 x i32>, <2 x i32>, <2 x i32>, <3 x i32>, <2 x i32>, <2 x i32>, <2 x i32>, float, float, float, float, float, float, float, float, float) #0 {
+main_body:
+  %20 = getelementptr <16 x i8> addrspace(2)* %0, i32 0
+  %21 = load <16 x i8> addrspace(2)* %20, !tbaa !0
+  %22 = call float @llvm.SI.load.const(<16 x i8> %21, i32 0)
+  %23 = call float @llvm.SI.load.const(<16 x i8> %21, i32 4)
+  %24 = call float @llvm.SI.load.const(<16 x i8> %21, i32 8)
+  %25 = call float @llvm.SI.load.const(<16 x i8> %21, i32 12)
+  %26 = fptosi float %25 to i32
+  %27 = bitcast i32 %26 to float
+  %28 = bitcast float %27 to i32
+  br label %LOOP
+
+LOOP:                                             ; preds = %ENDIF, %main_body
+  %temp4.0 = phi float [ %22, %main_body ], [ %temp5.0, %ENDIF ]
+  %temp5.0 = phi float [ %23, %main_body ], [ %temp6.0, %ENDIF ]
+  %temp6.0 = phi float [ %24, %main_body ], [ %temp4.0, %ENDIF ]
+  %temp8.0 = phi float [ 0.000000e+00, %main_body ], [ %37, %ENDIF ]
+  %29 = bitcast float %temp8.0 to i32
+  %30 = icmp sge i32 %29, %28
+  %31 = sext i1 %30 to i32
+  %32 = bitcast i32 %31 to float
+  %33 = bitcast float %32 to i32
+  %34 = icmp ne i32 %33, 0
+  br i1 %34, label %IF, label %ENDIF
+
+IF:                                               ; preds = %LOOP
+  call void @llvm.SI.export(i32 15, i32 1, i32 1, i32 0, i32 0, float %temp4.0, float %temp5.0, float %temp6.0, float 1.000000e+00)
+  ret void
+
+ENDIF:                                            ; preds = %LOOP
+  %35 = bitcast float %temp8.0 to i32
+  %36 = add i32 %35, 1
+  %37 = bitcast i32 %36 to float
+  br label %LOOP
+}
+
+; Function Attrs: nounwind readnone
+declare float @llvm.SI.load.const(<16 x i8>, i32) #1
+
+; Function Attrs: readonly
+declare float @fabs(float) #2
+
+declare void @llvm.SI.export(i32, i32, i32, i32, i32, float, float, float, float)
+
+attributes #0 = { "ShaderType"="0" }
+attributes #1 = { nounwind readnone }
+attributes #2 = { readonly }
+
+!0 = metadata !{metadata !"const", null, i32 1}
+