Index: lib/Target/R600/AMDGPUAsmPrinter.cpp
===================================================================
--- lib/Target/R600/AMDGPUAsmPrinter.cpp
+++ lib/Target/R600/AMDGPUAsmPrinter.cpp
@@ -309,7 +309,7 @@
           llvm_unreachable("Unknown register class");
         }
         unsigned hwReg = RI->getEncodingValue(reg) & 0xff;
-        unsigned maxUsed = hwReg + width - 1;
+        unsigned maxUsed = hwReg + width;
         if (isSGPR) {
           MaxSGPR = maxUsed > MaxSGPR ? maxUsed : MaxSGPR;
         } else {
Index: test/CodeGen/R600/register-count-comments.ll
===================================================================
--- test/CodeGen/R600/register-count-comments.ll
+++ test/CodeGen/R600/register-count-comments.ll
@@ -1,4 +1,4 @@
-; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs< %s | FileCheck -check-prefix=SI %s
+; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs -asm-verbose < %s | FileCheck -check-prefix=SI %s
 
 declare i32 @llvm.SI.tid() nounwind readnone
 
@@ -18,3 +18,10 @@
   store i32 %result, i32 addrspace(1)* %outptr, align 4
   ret void
 }
+
+; SI-LABEL: @one_vgpr_used
+; SI: NumVgprs: 1
+define void @one_vgpr_used(i32 addrspace(1)* %out, i32 %x) nounwind {
+  store i32 %x, i32 addrspace(1)* %out, align 4
+  ret void
+}