The method of doing the matching with a 'select' instruction was wrong. The
original code was matching like this:
if (match(A, m_Not(m_Value(B))))
B was already matched as a 'select' instruction. However, this isn't matching
what we think it's matching. It would match B as a 'Value', so basically
anything would match to it. In this case, a Constant matched. B was replaced
with a constant representation. And then the wrong value would be used in the
SelectInst::Create statement, causing a crash.
After thinking on this for a moment, and after Nick L. told me how the pattern
matching stuff was supposed to work, the solution was to match NOT an m_Value,
but an m_Select.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58946 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/FrontendC/2008-11-08-InstCombineSelect.c b/test/FrontendC/2008-11-08-InstCombineSelect.c
new file mode 100644
index 0000000..70c8d3a
--- /dev/null
+++ b/test/FrontendC/2008-11-08-InstCombineSelect.c
@@ -0,0 +1,17 @@
+// RUN: %llvmgcc %s -S -emit-llvm -O2 -o -
+// PR3028
+
+int g_187;
+int g_204;
+int g_434;
+
+int func_89 (void)
+{
+ return 1;
+}
+
+void func_20 (int p_22)
+{
+ if (1 & p_22 | g_204 & (1 < g_187) - func_89 ())
+ g_434 = 1;
+}