Teach ScalarEvolution to make use of no-overflow flags when

analyzing add recurrences.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77034 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 40 insertions, 0 deletions

diff --git a/test/Analysis/ScalarEvolution/nsw.ll b/test/Analysis/ScalarEvolution/nsw.ll
new file mode 100644
index 0000000000..245ed6f36b
--- /dev/null
+++ b/test/Analysis/ScalarEvolution/nsw.ll
@@ -0,0 +1,40 @@
+; RUN: llvm-as < %s | opt -analyze -scalar-evolution -disable-output | grep { -->  {.*,+,.*}<bb>} | count 8
+
+; The addrecs in this loop are analyzable only by using nsw information.
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64"
+
+define void @foo(double* %p) nounwind {
+entry:
+	%tmp = load double* %p, align 8		; <double> [#uses=1]
+	%tmp1 = fcmp ogt double %tmp, 2.000000e+00		; <i1> [#uses=1]
+	br i1 %tmp1, label %bb.nph, label %return
+
+bb.nph:		; preds = %entry
+	br label %bb
+
+bb:		; preds = %bb1, %bb.nph
+	%i.01 = phi i32 [ %tmp8, %bb1 ], [ 0, %bb.nph ]		; <i32> [#uses=3]
+	%tmp2 = sext i32 %i.01 to i64		; <i64> [#uses=1]
+	%tmp3 = getelementptr double* %p, i64 %tmp2		; <double*> [#uses=1]
+	%tmp4 = load double* %tmp3, align 8		; <double> [#uses=1]
+	%tmp5 = fmul double %tmp4, 9.200000e+00		; <double> [#uses=1]
+	%tmp6 = sext i32 %i.01 to i64		; <i64> [#uses=1]
+	%tmp7 = getelementptr double* %p, i64 %tmp6		; <double*> [#uses=1]
+	store double %tmp5, double* %tmp7, align 8
+	%tmp8 = nsw add i32 %i.01, 1		; <i32> [#uses=2]
+	br label %bb1
+
+bb1:		; preds = %bb
+	%phitmp = sext i32 %tmp8 to i64		; <i64> [#uses=1]
+	%tmp9 = getelementptr double* %p, i64 %phitmp		; <double*> [#uses=1]
+	%tmp10 = load double* %tmp9, align 8		; <double> [#uses=1]
+	%tmp11 = fcmp ogt double %tmp10, 2.000000e+00		; <i1> [#uses=1]
+	br i1 %tmp11, label %bb, label %bb1.return_crit_edge
+
+bb1.return_crit_edge:		; preds = %bb1
+	br label %return
+
+return:		; preds = %bb1.return_crit_edge, %entry
+	ret void
+}