llvm-6502/test/CodeGen/Hexagon/hwloop-wrap.ll
Brendon Cahoon 23b0065f29 [Hexagon] Check for underflow/wrap in hardware loop pass
If the loop trip count may underflow or wrap, the compiler should
not generate a hardware loop since the trip count will be
incorrect.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237365 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-14 14:15:08 +00:00

23 lines
611 B
LLVM

; RUN: llc -march=hexagon -mcpu=hexagonv5 < %s | FileCheck %s
; We shouldn't generate a hardware loop in this case because the initial
; value may be zero, which means the endloop instruction will not decrement
; the loop counter, and the loop will execute only once.
; CHECK-NOT: loop0
define void @foo(i32 %count, i32 %v) #0 {
entry:
br label %do.body
do.body:
%count.addr.0 = phi i32 [ %count, %entry ], [ %dec, %do.body ]
tail call void asm sideeffect "nop", ""() #1
%dec = add i32 %count.addr.0, -1
%cmp = icmp eq i32 %dec, 0
br i1 %cmp, label %do.end, label %do.body
do.end:
ret void
}