[Test] Add XFAIL test for PR55689

SCEV issues in dynamically unreached code, see details at https://github.com/llvm/llvm-project/issues/55689

1st reduced test by Nikic!

diff --git a/llvm/test/Transforms/IndVarSimplify/pr55689.ll b/llvm/test/Transforms/IndVarSimplify/pr55689.ll
new file mode 100644 (file)
index 0000000..c5565af
--- /dev/null
+++ b/llvm/test/Transforms/IndVarSimplify/pr55689.ll
@@ -0,0 +1,47 @@
+; RUN: opt -S -passes='loop(indvars)' -verify-scev < %s | FileCheck %s
+
+; REQUIRES: asserts
+; XFAIL: *
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:1-p2:32:8:8:32-ni:2"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @test_01(i1 %b) {
+; CHECK-LABEL: test_01
+entry:
+  %b.ext = zext i1 %b to i32
+  %zero = and i32 %b.ext, 2
+  %precond = icmp ne i32 %zero, 0
+  call void @llvm.assume(i1 %precond)
+  br label %loop
+
+loop:
+  %iv = phi i16 [ 0, %entry ], [ %iv.next, %loop ]
+  %iv.next = add i16 %iv, 1
+  %cond = icmp slt i16 %iv, 1
+  br i1 %cond, label %loop, label %exit
+
+exit:
+  ret void
+}
+
+define void @test_02() {
+; CHECK-LABEL: test_02
+entry:
+  %tmp = and i1 false, undef
+  br i1 %tmp, label %preheader, label %unreached
+
+preheader:                                              ; preds = %entry
+  br label %loop
+
+loop:                                              ; preds = %loop, %preheader
+  %tmp3 = phi i32 [ 2, %preheader ], [ %tmp4, %loop ]
+  %tmp4 = add nuw nsw i32 %tmp3, 1
+  %tmp5 = icmp ugt i32 %tmp3, 74
+  br i1 %tmp5, label %unreached, label %loop
+
+unreached:                                              ; preds = %loop
+  unreachable
+}
+
+declare void @llvm.assume(i1)