Rename test pr30298.ll to shrink_vmul_sse.ll, to make the name more m…

…eaningful, NFC.

Add PR number and comment in pr30298.ll to explain what is testing.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280843 91177308-0d34-0410-b5e6-96231b3b80d8

test/CodeGen/X86/pr30298.ll → test/CodeGen/X86/shrink_vmul_sse.ll

@@ -1,4 +1,8 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+;
+; PR30298: Check if the target doesn't have SSE2, compiler will not crash
+; or generate incorrect code because of vector mul width shrinking optimization.
+;
 ; RUN: llc -mtriple=i386-pc-linux-gnu -mattr=+sse < %s | FileCheck %s
 
 @c = external global i32*, align 8