R600/SI: Implement isLegalAddressingMode

The default assumes that a 16-bit signed offset is used.
LDS instruction use a 16-bit unsigned offset, so it wasn't
being used in some cases where it was assumed a negative offset
could be used.

More should be done here, but first isLegalAddressingMode needs
to gain an addressing mode argument. For now, copy most of the rest
of the default implementation with the immediate offset change.

llvm-svn: 215732

1 files changed, 60 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/R600/ds-negative-offset-addressing-mode-loop.ll b/llvm/test/CodeGen/R600/ds-negative-offset-addressing-mode-loop.ll
new file mode 100644
index 00000000000..d768c0e4ba9
--- /dev/null
+++ b/llvm/test/CodeGen/R600/ds-negative-offset-addressing-mode-loop.ll
@@ -0,0 +1,60 @@
+; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs < %s | FileCheck -check-prefix=SI %s
+
+declare i32 @llvm.r600.read.tidig.x() #0
+declare void @llvm.AMDGPU.barrier.local() #1
+
+; Function Attrs: nounwind
+; SI-LABEL: @signed_ds_offset_addressing_loop
+; SI: BB0_1:
+; SI: V_ADD_I32_e32 [[VADDR:v[0-9]+]],
+; SI-DAG: DS_READ_B32 v{{[0-9]+}}, [[VADDR]], 0x0
+; SI-DAG: DS_READ_B32 v{{[0-9]+}}, [[VADDR]], 0x4
+; SI-DAG: DS_READ_B32 v{{[0-9]+}}, [[VADDR]], 0x80
+; SI-DAG: DS_READ_B32 v{{[0-9]+}}, [[VADDR]], 0x84
+; SI-DAG: DS_READ_B32 v{{[0-9]+}}, [[VADDR]], 0x100
+; SI: S_ENDPGM
+define void @signed_ds_offset_addressing_loop(float addrspace(1)* noalias nocapture %out, float addrspace(3)* noalias nocapture readonly %lptr, i32 %n) #2 {
+entry:
+  %x.i = tail call i32 @llvm.r600.read.tidig.x() #0
+  %mul = shl nsw i32 %x.i, 1
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %sum.03 = phi float [ 0.000000e+00, %entry ], [ %add13, %for.body ]
+  %offset.02 = phi i32 [ %mul, %entry ], [ %add14, %for.body ]
+  %k.01 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
+  tail call void @llvm.AMDGPU.barrier.local() #1
+  %arrayidx = getelementptr inbounds float addrspace(3)* %lptr, i32 %offset.02
+  %tmp = load float addrspace(3)* %arrayidx, align 4
+  %add1 = add nsw i32 %offset.02, 1
+  %arrayidx2 = getelementptr inbounds float addrspace(3)* %lptr, i32 %add1
+  %tmp1 = load float addrspace(3)* %arrayidx2, align 4
+  %add3 = add nsw i32 %offset.02, 32
+  %arrayidx4 = getelementptr inbounds float addrspace(3)* %lptr, i32 %add3
+  %tmp2 = load float addrspace(3)* %arrayidx4, align 4
+  %add5 = add nsw i32 %offset.02, 33
+  %arrayidx6 = getelementptr inbounds float addrspace(3)* %lptr, i32 %add5
+  %tmp3 = load float addrspace(3)* %arrayidx6, align 4
+  %add7 = add nsw i32 %offset.02, 64
+  %arrayidx8 = getelementptr inbounds float addrspace(3)* %lptr, i32 %add7
+  %tmp4 = load float addrspace(3)* %arrayidx8, align 4
+  %add9 = fadd float %tmp, %tmp1
+  %add10 = fadd float %add9, %tmp2
+  %add11 = fadd float %add10, %tmp3
+  %add12 = fadd float %add11, %tmp4
+  %add13 = fadd float %sum.03, %add12
+  %inc = add nsw i32 %k.01, 1
+  %add14 = add nsw i32 %offset.02, 97
+  %exitcond = icmp eq i32 %inc, 8
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  %tmp5 = sext i32 %x.i to i64
+  %arrayidx15 = getelementptr inbounds float addrspace(1)* %out, i64 %tmp5
+  store float %add13, float addrspace(1)* %arrayidx15, align 4
+  ret void
+}
+
+attributes #0 = { nounwind readnone }
+attributes #1 = { noduplicate nounwind }
+attributes #2 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }