The patchpoint lowering logic would crash with live constants equal to
the tombstone or empty keys of a DenseMap<int64_t, T>.  This patch
fixes the issue (and adds a tests case).

llvm-svn: 221214
diff --git a/llvm/test/CodeGen/X86/stackmap-large-constants.ll b/llvm/test/CodeGen/X86/stackmap-large-constants.ll
new file mode 100644
index 0000000..85e7a06
--- /dev/null
+++ b/llvm/test/CodeGen/X86/stackmap-large-constants.ll
@@ -0,0 +1,83 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
+
+; CHECK-LABEL:	.section	__LLVM_STACKMAPS,__llvm_stackmaps
+; CHECK-NEXT: __LLVM_StackMaps:
+; version
+; CHECK-NEXT: 	.byte	1
+; reserved
+; CHECK-NEXT: 	.byte	0
+; reserved
+; CHECK-NEXT: 	.short	0
+; # functions
+; CHECK-NEXT: 	.long	2
+; # constants
+; CHECK-NEXT: 	.long	2
+; # records
+; CHECK-NEXT: 	.long	2
+; function address & stack size
+; CHECK-NEXT: 	.quad	_foo
+; CHECK-NEXT: 	.quad	8
+; function address & stack size
+; CHECK-NEXT: 	.quad	_bar
+; CHECK-NEXT: 	.quad	8
+
+; Constants Array:
+; CHECK-NEXT: 	.quad	9223372036854775807
+; CHECK-NEXT: 	.quad	-9223372036854775808
+
+; Patchpoint ID
+; CHECK-NEXT: 	.quad	0
+; Instruction offset
+; CHECK-NEXT: 	.long	Ltmp3-_foo
+; reserved
+; CHECK-NEXT: 	.short	0
+; # locations
+; CHECK-NEXT: 	.short	1
+; ConstantIndex
+; CHECK-NEXT: 	.byte	5
+; reserved
+; CHECK-NEXT: 	.byte	8
+; Dwarf RegNum
+; CHECK-NEXT: 	.short	0
+; Offset
+; CHECK-NEXT: 	.long	0
+; padding
+; CHECK-NEXT: 	.short	0
+; NumLiveOuts
+; CHECK-NEXT: 	.short	0
+
+; CHECK-NEXT: 	.align	3
+
+declare void @llvm.experimental.stackmap(i64, i32, ...)
+
+define void @foo() {
+  tail call void (i64, i32, ...)* @llvm.experimental.stackmap(i64 0, i32 0, i64 9223372036854775807)
+  ret void
+}
+
+; Patchpoint ID
+; CHECK-NEXT: 	.quad	0
+; Instruction Offset
+; CHECK-NEXT: 	.long	Ltmp7-_bar
+; reserved
+; CHECK-NEXT: 	.short	0
+; # locations
+; CHECK-NEXT: 	.short	1
+; ConstantIndex
+; CHECK-NEXT: 	.byte	5
+; reserved
+; CHECK-NEXT: 	.byte	8
+; Dwarf RegNum
+; CHECK-NEXT: 	.short	0
+; Offset
+; CHECK-NEXT: 	.long	1
+; padding
+; CHECK-NEXT: 	.short	0
+; NumLiveOuts
+; CHECK-NEXT: 	.short	0
+
+
+define void @bar() {
+  tail call void (i64, i32, ...)* @llvm.experimental.stackmap(i64 0, i32 0, i64 -9223372036854775808)
+  ret void
+}