[Hexagon] Fixes to the bitsplit generation

- Fix the insertion point, which occasionally could have been incorrect.
- Avoid creating multiple bitsplits with the same operands, if an old one
  could be reused.

llvm-svn: 297414

1 files changed, 33 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/Hexagon/bit-bitsplit-at.ll b/llvm/test/CodeGen/Hexagon/bit-bitsplit-at.ll
new file mode 100644
index 00000000000..87d535fd0f2
--- /dev/null
+++ b/llvm/test/CodeGen/Hexagon/bit-bitsplit-at.ll
@@ -0,0 +1,33 @@
+; RUN: llc -march=hexagon < %s | FileCheck %s
+; REQUIRES: asserts
+
+; This testcase used to crash due to putting the bitsplit instruction in a
+; wrong place.
+; CHECK: bitsplit
+
+target triple = "hexagon"
+
+define hidden fastcc i32 @fred(i32 %a0) unnamed_addr #0 {
+b1:
+  %v2 = lshr i32 %a0, 16
+  %v3 = trunc i32 %v2 to i8
+  br i1 undef, label %b6, label %b4
+
+b4:                                               ; preds = %b1
+  %v5 = and i32 %a0, 65535
+  br i1 undef, label %b8, label %b9
+
+b6:                                               ; preds = %b1
+  %v7 = and i32 %a0, 65535
+  br label %b9
+
+b8:                                               ; preds = %b4
+  store i8 %v3, i8* undef, align 2
+  unreachable
+
+b9:                                               ; preds = %b6, %b4
+  %v10 = phi i32 [ %v7, %b6 ], [ %v5, %b4 ]
+  ret i32 %v10
+}
+
+attributes #0 = { nounwind optsize "target-cpu"="hexagonv60" "target-features"="-hvx-double,-long-calls" }