Fix pr3954. The register scavenger asserts for inline assembly with
register destinations that are tied to source operands. The
TargetInstrDescr::findTiedToSrcOperand method silently fails for inline
assembly. The existing MachineInstr::isRegReDefinedByTwoAddr was very
close to doing what is needed, so this revision makes a few changes to
that method and also renames it to isRegTiedToUseOperand (for consistency
with the very similar isRegTiedToDefOperand and because it handles both
two-address instructions and inline assembly with tied registers).
llvm-svn: 68714
diff --git a/llvm/test/CodeGen/ARM/2009-04-09-RegScavengerAsm.ll b/llvm/test/CodeGen/ARM/2009-04-09-RegScavengerAsm.ll
new file mode 100644
index 0000000..223fa0f
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/2009-04-09-RegScavengerAsm.ll
@@ -0,0 +1,14 @@
+; RUN: llvm-as < %s | llc -march=arm
+; PR3954
+
+define void @foo(...) nounwind {
+entry:
+ %rr = alloca i32 ; <i32*> [#uses=2]
+ %0 = load i32* %rr ; <i32> [#uses=1]
+ %1 = call i32 asm "nop", "=r,0"(i32 %0) nounwind ; <i32> [#uses=1]
+ store i32 %1, i32* %rr
+ br label %return
+
+return: ; preds = %entry
+ ret void
+}