CreateVirtualRegisters does trivial copy coalescing. If a node def is used by a single CopyToReg, it reuses the virtual register assigned to the CopyToReg. This won't work for SDNode that is a clone or is itself cloned. Disable this optimization for those nodes or it can end up with non-SSA machine instructions.
llvm-svn: 62356
diff --git a/llvm/test/CodeGen/X86/2009-01-16-SchedulerBug.ll b/llvm/test/CodeGen/X86/2009-01-16-SchedulerBug.ll
new file mode 100644
index 0000000..ff20dc1
--- /dev/null
+++ b/llvm/test/CodeGen/X86/2009-01-16-SchedulerBug.ll
@@ -0,0 +1,50 @@
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin
+; rdar://6501631
+
+ %CF = type { %Register }
+ %XXV = type { i32 (...)** }
+ %Register = type { %"struct.XXC::BCFs", i32 }
+ %"struct.XXC::BCFs" = type { i32 }
+
+declare { i32, i1 } @llvm.sadd.with.overflow.i32(i32, i32) nounwind
+
+define fastcc %XXV* @bar(%CF* %call_frame, %XXV** %exception) nounwind {
+prologue:
+ %param_x = load %XXV** null ; <%XXV*> [#uses=1]
+ %unique_1.i = ptrtoint %XXV* %param_x to i1 ; <i1> [#uses=1]
+ br i1 %unique_1.i, label %NextVerify42, label %FailedVerify
+
+NextVerify42: ; preds = %prologue
+ %param_y = load %XXV** null ; <%XXV*> [#uses=1]
+ %unique_1.i58 = ptrtoint %XXV* %param_y to i1 ; <i1> [#uses=1]
+ br i1 %unique_1.i58, label %function_setup.cont, label %FailedVerify
+
+function_setup.cont: ; preds = %NextVerify42
+ br i1 false, label %label13, label %label
+
+label: ; preds = %function_setup.cont
+ %has_exn = icmp eq %XXV* null, null ; <i1> [#uses=1]
+ br i1 %has_exn, label %kjsNumberLiteral.exit, label %handle_exception
+
+kjsNumberLiteral.exit: ; preds = %label
+ %0 = call { i32, i1 } @llvm.sadd.with.overflow.i32(i32 0, i32 0) ; <{ i32, i1 }> [#uses=2]
+ %intAdd = extractvalue { i32, i1 } %0, 0 ; <i32> [#uses=2]
+ %intAddOverflow = extractvalue { i32, i1 } %0, 1 ; <i1> [#uses=1]
+ %toint56 = ashr i32 %intAdd, 1 ; <i32> [#uses=1]
+ %toFP57 = sitofp i32 %toint56 to double ; <double> [#uses=1]
+ br i1 %intAddOverflow, label %rematerializeAdd, label %label13
+
+label13: ; preds = %kjsNumberLiteral.exit, %function_setup.cont
+ %var_lr1.0 = phi double [ %toFP57, %kjsNumberLiteral.exit ], [ 0.000000e+00, %function_setup.cont ] ; <double> [#uses=0]
+ unreachable
+
+FailedVerify: ; preds = %NextVerify42, %prologue
+ ret %XXV* null
+
+rematerializeAdd: ; preds = %kjsNumberLiteral.exit
+ %rematerializedInt = sub i32 %intAdd, 0 ; <i32> [#uses=0]
+ ret %XXV* null
+
+handle_exception: ; preds = %label
+ ret %XXV* undef
+}