New testcase for a problem that occurred in 132.ijpeg

llvm-svn: 19630

1 files changed, 16 insertions, 0 deletions

diff --git a/llvm/test/Regression/CodeGen/X86/2005-01-17-CycleInDAG.ll b/llvm/test/Regression/CodeGen/X86/2005-01-17-CycleInDAG.ll
new file mode 100644
index 00000000000..fdfed6cf41d
--- /dev/null
+++ b/llvm/test/Regression/CodeGen/X86/2005-01-17-CycleInDAG.ll
@@ -0,0 +1,16 @@
+; This testcase was distilled from 132.ijpeg.  Bsaically we cannot fold the
+; load into the sub instruction here as it induces a cycle in the dag, which
+; is invalid code (there is no correct way to order the instruction).  Check
+; that we do not fold the load into the sub.
+
+; RUN: llvm-as < %s | llc -march=x86 -disable-pattern-isel=0 | not grep 'sub.*GLOBAL'
+
+%GLOBAL = external global int
+
+int %test(int* %P1, int* %P2, int* %P3) {
+   %L = load int* %GLOBAL
+   store int 12, int* %P2
+   %Y = load int* %P3
+   %Z = sub int %Y, %L
+   ret int %Z
+}