[mips] Add code to do tail call optimization.

Currently, it is enabled only if option "enable-mips-tail-calls" is given and
all of the callee's arguments are passed in registers.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166342 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 100 insertions, 0 deletions

diff --git a/test/CodeGen/Mips/tailcall.ll b/test/CodeGen/Mips/tailcall.ll
new file mode 100644
index 0000000000..4989636a20
--- /dev/null
+++ b/test/CodeGen/Mips/tailcall.ll
@@ -0,0 +1,100 @@
+; RUN: llc -march=mipsel -relocation-model=pic -enable-mips-tail-calls < %s | \
+; RUN: FileCheck %s -check-prefix=PIC32
+; RUN: llc -march=mipsel -relocation-model=static \
+; RUN: -enable-mips-tail-calls < %s | FileCheck %s -check-prefix=STATIC32
+; RUN: llc -march=mips64el -mcpu=mips64r2 -mattr=+n64 -enable-mips-tail-calls \
+; RUN: < %s | FileCheck %s -check-prefix=N64
+
+@g0 = common global i32 0, align 4
+@g1 = common global i32 0, align 4
+@g2 = common global i32 0, align 4
+@g3 = common global i32 0, align 4
+@g4 = common global i32 0, align 4
+@g5 = common global i32 0, align 4
+@g6 = common global i32 0, align 4
+@g7 = common global i32 0, align 4
+@g8 = common global i32 0, align 4
+@g9 = common global i32 0, align 4
+
+define i32 @caller1(i32 %a0) nounwind {
+entry:
+; PIC32-NOT: jalr
+; STATIC32-NOT: jal
+; N64-NOT: jalr
+
+  %call = tail call i32 @callee1(i32 1, i32 1, i32 1, i32 %a0) nounwind
+  ret i32 %call
+}
+
+declare i32 @callee1(i32, i32, i32, i32)
+
+define i32 @caller2(i32 %a0, i32 %a1, i32 %a2, i32 %a3) nounwind {
+entry:
+; PIC32: jalr
+; STATIC32: jal
+; N64-NOT: jalr
+
+  %call = tail call i32 @callee2(i32 1, i32 %a0, i32 %a1, i32 %a2, i32 %a3) nounwind
+  ret i32 %call
+}
+
+declare i32 @callee2(i32, i32, i32, i32, i32)
+
+define i32 @caller3(i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %a4) nounwind {
+entry:
+; PIC32: jalr
+; STATIC32: jal
+; N64-NOT: jalr
+
+  %call = tail call i32 @callee3(i32 1, i32 1, i32 1, i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %a4) nounwind
+  ret i32 %call
+}
+
+declare i32 @callee3(i32, i32, i32, i32, i32, i32, i32, i32)
+
+define i32 @caller4(i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %a4, i32 %a5, i32 %a6, i32 %a7) nounwind {
+entry:
+; PIC32: jalr
+; STATIC32: jal
+; N64: jalr
+
+  %call = tail call i32 @callee4(i32 1, i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %a4, i32 %a5, i32 %a6, i32 %a7) nounwind
+  ret i32 %call
+}
+
+declare i32 @callee4(i32, i32, i32, i32, i32, i32, i32, i32, i32)
+
+define i32 @caller5() nounwind readonly {
+entry:
+; PIC32-NOT: jalr
+; STATIC32-NOT: jal
+; N64-NOT: jalr
+
+  %0 = load i32* @g0, align 4
+  %1 = load i32* @g1, align 4
+  %2 = load i32* @g2, align 4
+  %3 = load i32* @g3, align 4
+  %4 = load i32* @g4, align 4
+  %5 = load i32* @g5, align 4
+  %6 = load i32* @g6, align 4
+  %7 = load i32* @g7, align 4
+  %8 = load i32* @g8, align 4
+  %9 = load i32* @g9, align 4
+  %call = tail call fastcc i32 @callee5(i32 %0, i32 %1, i32 %2, i32 %3, i32 %4, i32 %5, i32 %6, i32 %7, i32 %8, i32 %9)
+  ret i32 %call
+}
+
+define internal fastcc i32 @callee5(i32 %a0, i32 %a1, i32 %a2, i32 %a3, i32 %a4, i32 %a5, i32 %a6, i32 %a7, i32 %a8, i32 %a9) nounwind readnone noinline {
+entry:
+  %add = add nsw i32 %a1, %a0
+  %add1 = add nsw i32 %add, %a2
+  %add2 = add nsw i32 %add1, %a3
+  %add3 = add nsw i32 %add2, %a4
+  %add4 = add nsw i32 %add3, %a5
+  %add5 = add nsw i32 %add4, %a6
+  %add6 = add nsw i32 %add5, %a7
+  %add7 = add nsw i32 %add6, %a8
+  %add8 = add nsw i32 %add7, %a9
+  ret i32 %add8
+}
+