Unit test for r140919, loop unroll heuristics.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141049 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/Transforms/LoopUnroll/2011-10-01-NoopTrunc.ll b/test/Transforms/LoopUnroll/2011-10-01-NoopTrunc.ll
new file mode 100644 (file)
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+++ b/test/Transforms/LoopUnroll/2011-10-01-NoopTrunc.ll
@@ -0,0 +1,36 @@
+; RUN: opt < %s -S -loop-unroll -unroll-threshold=150 | FileCheck %s
+;
+; Verify that trunc i64 to i32 is considered free by loop unrolling
+; heuristics when i32 is a native type.
+; This should result in full unrolling this loop with size=7, TC=19.
+; If the trunc were not free we would have 8*19=152 > 150.
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+
+; Check that for.body was unrolled 19 times.
+; CHECK: @test
+; CHECK: %0 = load
+; CHECK: %conv = sext i8 %0 to i32
+; CHECK: %add.1 = add nsw i32 %conv.1, %conv
+; CHECK: %add.18 = add nsw i32 %conv.18, %add.17
+; CHECK: ret i32 %add.18
+define i32 @test(i8* %arr) nounwind uwtable readnone {
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %sum.02 = phi i32 [ 0, %entry ], [ %add, %for.body ]
+  %arrayidx = getelementptr inbounds i8* %arr, i64 %indvars.iv
+  %0 = load i8* %arrayidx, align 1
+  %conv = sext i8 %0 to i32
+  %add = add nsw i32 %conv, %sum.02
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv1 = trunc i64 %indvars.iv.next to i32
+  %exitcond2 = icmp eq i32 %lftr.wideiv1, 19
+  br i1 %exitcond2, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  %add.lcssa = phi i32 [ %add, %for.body ]
+  ret i32 %add.lcssa
+}