llvm-6502/test/CodeGen/PowerPC/cr1eq-no-extra-moves.ll
Hal Finkel 82b3821208 Eliminate redundant CR moves on PPC32.
The 32-bit ABI requires CR bit 6 to be set if the call has fp arguments and
unset if it doesn't. The solution up to now was to insert a MachineNode to
set/unset the CR bit, which produces a CR vreg. This vreg was then copied
into CR bit 6. When the register allocator saw a bunch of these in the same
function, it allocated the set/unset CR bit in some random CR register (1
extra instruction) and then emitted CR moves before every vararg function
call, rather than just setting and unsetting CR bit 6 directly before every
vararg function call. This patch instead inserts a PPCcrset/PPCcrunset
instruction which are then matched by a dedicated instruction pattern.

Patch by Tobias von Koch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162725 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-28 02:10:27 +00:00

27 lines
1.0 KiB
LLVM

; RUN: llc < %s | FileCheck %s
target datalayout = "E-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v128:128:128-n32"
target triple = "powerpc-unknown-linux"
@.str = private unnamed_addr constant [3 x i8] c"%i\00", align 1
define void @test(i32 %count) nounwind {
entry:
; CHECK: crxor 6, 6, 6
%call = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([3 x i8]* @.str, i32 0, i32 0), i32 1) nounwind
%cmp2 = icmp sgt i32 %count, 0
br i1 %cmp2, label %for.body, label %for.end
for.body: ; preds = %entry, %for.body
%i.03 = phi i32 [ %inc, %for.body ], [ 0, %entry ]
; CHECK: crxor 6, 6, 6
%call1 = tail call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([3 x i8]* @.str, i32 0, i32 0), i32 1) nounwind
%inc = add nsw i32 %i.03, 1
%exitcond = icmp eq i32 %inc, %count
br i1 %exitcond, label %for.end, label %for.body
for.end: ; preds = %for.body, %entry
ret void
}
declare i32 @printf(i8* nocapture, ...) nounwind