DAGCombine: prevent formation of illegal ConstantFP nodes.
llvm-svn: 207850
diff --git a/llvm/test/CodeGen/ARM64/fp-contract-zero.ll b/llvm/test/CodeGen/ARM64/fp-contract-zero.ll
new file mode 100644
index 0000000..f982cbb
--- /dev/null
+++ b/llvm/test/CodeGen/ARM64/fp-contract-zero.ll
@@ -0,0 +1,14 @@
+; RUN: llc -mtriple=arm64 -fp-contract=fast -o - %s | FileCheck %s
+
+
+; Make sure we don't try to fold an fneg into +0.0, creating an illegal constant
+; -0.0. It's also good, though not essential, that we don't resort to a litpool.
+define double @test_fms_fold(double %a, double %b) {
+; CHECK-LABEL: test_fms_fold:
+; CHECK: fmov {{d[0-9]+}}, xzr
+; CHECK: ret
+ %mul = fmul double %a, 0.000000e+00
+ %mul1 = fmul double %b, 0.000000e+00
+ %sub = fsub double %mul, %mul1
+ ret double %sub
+}
\ No newline at end of file