ARM: fix yet another stack-folding bug
We were trying to fold the stack adjustment into the wrong instruction in the
situation where the entire basic-block was epilogue code. Really, it can only
ever be valid to do the folding precisely where the "add sp, ..." would be
placed so there's no need for a separate iterator to track that.
Should fix PR18136.
llvm-svn: 196493
diff --git a/llvm/test/CodeGen/ARM/fold-stack-adjust.ll b/llvm/test/CodeGen/ARM/fold-stack-adjust.ll
index 8bda768..8c60bca 100644
--- a/llvm/test/CodeGen/ARM/fold-stack-adjust.ll
+++ b/llvm/test/CodeGen/ARM/fold-stack-adjust.ll
@@ -124,3 +124,32 @@
ret double 1.0
}
+
+@dbl = global double 0.0
+
+; PR18136: there was a bug determining where the first eligible pop in a
+; basic-block was when the entire block was epilogue code.
+define void @test_fold_point(i1 %tst) minsize {
+; CHECK-LABEL: test_fold_point:
+
+ ; Important to check for beginning of basic block, because if it gets
+ ; if-converted the test is probably no longer checking what it should.
+; CHECK: {{LBB[0-9]+_2}}:
+; CHECK-NEXT: vpop {d7, d8}
+; CHECK-NEXT: pop {r4, pc}
+ ; We want some memory so there's a stack adjustment to fold...
+ %var = alloca i8, i32 8
+
+ ; We want a long-lived floating register so that a callee-saved dN is used and
+ ; there's both a vpop and a pop.
+ %live_val = load double* @dbl
+ br i1 %tst, label %true, label %end
+true:
+ call void @bar(i8* %var)
+ store double %live_val, double* @dbl
+ br label %end
+end:
+ ; We want the epilogue to be the only thing in a basic block so that we hit
+ ; the correct edge-case (first inst in block is correct one to adjust).
+ ret void
+}
\ No newline at end of file