llvm-6502/test/CodeGen/X86/pr3495.ll
Dale Johannesen c1acc3f764 Reverse a loop that is counting up to a maximum to
count down to 0 instead, under very restricted
circumstances.  Adjust 4 testcases in which this
optimization fires.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71439 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-11 17:15:42 +00:00

81 lines
3.3 KiB
LLVM

; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of reloads omited} | grep 2
; RUN: llvm-as < %s | llc -march=x86 -stats |& not grep {Number of available reloads turned into copies}
; RUN: llvm-as < %s | llc -march=x86 -stats |& grep {Number of machine instrs printed} | grep 38
; PR3495
; The loop reversal kicks in once here, resulting in one fewer instruction.
target triple = "i386-pc-linux-gnu"
@x = external global [8 x i32], align 32 ; <[8 x i32]*> [#uses=1]
@rows = external global [8 x i32], align 32 ; <[8 x i32]*> [#uses=2]
@up = external global [15 x i32], align 32 ; <[15 x i32]*> [#uses=2]
@down = external global [15 x i32], align 32 ; <[15 x i32]*> [#uses=1]
define i32 @queens(i32 %c) nounwind {
entry:
%tmp91 = add i32 %c, 1 ; <i32> [#uses=3]
%tmp135 = getelementptr [8 x i32]* @x, i32 0, i32 %tmp91 ; <i32*> [#uses=1]
br label %bb
bb: ; preds = %bb569, %entry
%r25.0.reg2mem.0 = phi i32 [ 0, %entry ], [ %indvar.next715, %bb569 ] ; <i32> [#uses=4]
%tmp27 = getelementptr [8 x i32]* @rows, i32 0, i32 %r25.0.reg2mem.0 ; <i32*> [#uses=1]
%tmp28 = load i32* %tmp27, align 4 ; <i32> [#uses=1]
%tmp29 = icmp eq i32 %tmp28, 0 ; <i1> [#uses=1]
br i1 %tmp29, label %bb569, label %bb31
bb31: ; preds = %bb
%tmp35 = sub i32 %r25.0.reg2mem.0, 0 ; <i32> [#uses=1]
%tmp36 = getelementptr [15 x i32]* @up, i32 0, i32 %tmp35 ; <i32*> [#uses=1]
%tmp37 = load i32* %tmp36, align 4 ; <i32> [#uses=1]
%tmp38 = icmp eq i32 %tmp37, 0 ; <i1> [#uses=1]
br i1 %tmp38, label %bb569, label %bb41
bb41: ; preds = %bb31
%tmp54 = sub i32 %r25.0.reg2mem.0, %c ; <i32> [#uses=1]
%tmp55 = add i32 %tmp54, 7 ; <i32> [#uses=1]
%tmp62 = getelementptr [15 x i32]* @up, i32 0, i32 %tmp55 ; <i32*> [#uses=2]
store i32 0, i32* %tmp62, align 4
br label %bb92
bb92: ; preds = %bb545, %bb41
%r20.0.reg2mem.0 = phi i32 [ 0, %bb41 ], [ %indvar.next711, %bb545 ] ; <i32> [#uses=5]
%tmp94 = getelementptr [8 x i32]* @rows, i32 0, i32 %r20.0.reg2mem.0 ; <i32*> [#uses=1]
%tmp95 = load i32* %tmp94, align 4 ; <i32> [#uses=0]
%tmp112 = add i32 %r20.0.reg2mem.0, %tmp91 ; <i32> [#uses=1]
%tmp113 = getelementptr [15 x i32]* @down, i32 0, i32 %tmp112 ; <i32*> [#uses=2]
%tmp114 = load i32* %tmp113, align 4 ; <i32> [#uses=1]
%tmp115 = icmp eq i32 %tmp114, 0 ; <i1> [#uses=1]
br i1 %tmp115, label %bb545, label %bb118
bb118: ; preds = %bb92
%tmp122 = sub i32 %r20.0.reg2mem.0, %tmp91 ; <i32> [#uses=0]
store i32 0, i32* %tmp113, align 4
store i32 %r20.0.reg2mem.0, i32* %tmp135, align 4
br label %bb142
bb142: ; preds = %bb142, %bb118
%k18.0.reg2mem.0 = phi i32 [ 0, %bb118 ], [ %indvar.next709, %bb142 ] ; <i32> [#uses=1]
%indvar.next709 = add i32 %k18.0.reg2mem.0, 1 ; <i32> [#uses=2]
%exitcond710 = icmp eq i32 %indvar.next709, 8 ; <i1> [#uses=1]
br i1 %exitcond710, label %bb155, label %bb142
bb155: ; preds = %bb142
%tmp156 = tail call i32 @putchar(i32 10) nounwind ; <i32> [#uses=0]
br label %bb545
bb545: ; preds = %bb155, %bb92
%indvar.next711 = add i32 %r20.0.reg2mem.0, 1 ; <i32> [#uses=2]
%exitcond712 = icmp eq i32 %indvar.next711, 8 ; <i1> [#uses=1]
br i1 %exitcond712, label %bb553, label %bb92
bb553: ; preds = %bb545
store i32 1, i32* %tmp62, align 4
br label %bb569
bb569: ; preds = %bb553, %bb31, %bb
%indvar.next715 = add i32 %r25.0.reg2mem.0, 1 ; <i32> [#uses=1]
br label %bb
}
declare i32 @putchar(i32)