[SPARC] Cleanup handling of the Y/ASR registers.

- Implement copying ASR to/from GPR regs.
- Mark ASRs as non-allocatable, so it won't try to arbitrarily use
  them inappropriately.
- Instead of inserting explicit WRASR/RDASR nodes in the MUL/DIV
  routines, just do normal register copies.
- Also...mark div as using Y, not just writing it.

Added a test case with some code which previously died with an
assertion failure (with -O0), or produced wrong code (otherwise).

(Third time's the charm?)

Differential Revision: http://reviews.llvm.org/D10401

llvm-svn: 241686

1 files changed, 21 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/SPARC/multiple-div.ll b/llvm/test/CodeGen/SPARC/multiple-div.ll
new file mode 100644
index 00000000000..6934f69ac18
--- /dev/null
+++ b/llvm/test/CodeGen/SPARC/multiple-div.ll
@@ -0,0 +1,21 @@
+; RUN: llc < %s -march=sparc | FileCheck %s
+; RUN: llc -O0 < %s -march=sparc | FileCheck %s
+
+;; llc -O0 used to try to spill Y to the stack, which isn't possible,
+;; and then crashed. Additionally, in -O1, it would omit the second
+;; apparently-redundant wr to %y, which is not actually redundant
+;; because the spec says to treat %y as potentially-written by udiv.
+
+; CHECK-LABEL: two_divides:
+; CHECK: wr %g0, %g0, %y
+; CHECK: udiv
+; CHECK: wr %g0, %g0, %y
+; CHECK: udiv
+; CHECK: add
+
+define i32 @two_divides(i32 %a, i32 %b) {
+  %r = udiv i32 %a, %b
+  %r2 = udiv i32 %b, %a
+  %r3 = add i32 %r, %r2
+  ret i32 %r3
+}