Fix LSR's IV sorting function to explicitly sort by bitwidth

after sorting by stride value. This prevents it from missing
IV reuse opportunities in a host-sensitive manner.

llvm-svn: 64415

1 files changed, 22 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/lsr-sort.ll b/llvm/test/CodeGen/X86/lsr-sort.ll
new file mode 100644
index 00000000000..00e1d694ef4
--- /dev/null
+++ b/llvm/test/CodeGen/X86/lsr-sort.ll
@@ -0,0 +1,22 @@
+; RUN: llvm-as < %s | llc -march=x86-64 > %t
+; RUN: grep inc %t | count 1
+; RUN: not grep incw %t
+
+@X = common global i16 0		; <i16*> [#uses=1]
+
+define void @foo(i32 %N) nounwind {
+entry:
+	%0 = icmp sgt i32 %N, 0		; <i1> [#uses=1]
+	br i1 %0, label %bb, label %return
+
+bb:		; preds = %bb, %entry
+	%i.03 = phi i32 [ 0, %entry ], [ %indvar.next, %bb ]		; <i32> [#uses=2]
+	%1 = trunc i32 %i.03 to i16		; <i16> [#uses=1]
+	volatile store i16 %1, i16* @X, align 2
+	%indvar.next = add i32 %i.03, 1		; <i32> [#uses=2]
+	%exitcond = icmp eq i32 %indvar.next, %N		; <i1> [#uses=1]
+	br i1 %exitcond, label %return, label %bb
+
+return:		; preds = %bb, %entry
+	ret void
+}