llvm-6502/test/Transforms/LoopStrengthReduce/uglygep.ll
Quentin Colombet 5b00f4edcb Modify how the formulae are rated in Loop Strength Reduce.
Namely, check if the target allows to fold more that one register in the
addressing mode and if yes, adjust the cost accordingly.

Prior to this commit, reg1 + scale * reg2 accesses were artificially preferred
to reg1 + reg2 accesses. Indeed, the cost model wrongly assumed that reg1 + reg2
needs a temporary register for the computation, whereas it was correctly
estimated for reg1 + scale * reg2.

<rdar://problem/13973908>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183021 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-31 17:20:29 +00:00

123 lines
4.7 KiB
LLVM

; RUN: opt < %s -loop-reduce -S | FileCheck %s
; LSR shouldn't consider %t8 to be an interesting user of %t6, and it
; should be able to form pretty GEPs.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
define void @Z4() nounwind {
; CHECK: define void @Z4
bb:
br label %bb3
bb1: ; preds = %bb3
br i1 undef, label %bb10, label %bb2
bb2: ; preds = %bb1
%t = add i64 %t4, 1 ; <i64> [#uses=1]
br label %bb3
bb3: ; preds = %bb2, %bb
%t4 = phi i64 [ %t, %bb2 ], [ 0, %bb ] ; <i64> [#uses=3]
br label %bb1
; CHECK: bb10:
; CHECK-NEXT: %t7 = icmp eq i64 %t4, 0
; Host %t2 computation outside the loop.
; CHECK-NEXT: [[SCEVGEP:%[^ ]+]] = getelementptr i8* undef, i64 %t4
; CHECK-NEXT: br label %bb14
bb10: ; preds = %bb9
%t7 = icmp eq i64 %t4, 0 ; <i1> [#uses=1]
%t3 = add i64 %t4, 16 ; <i64> [#uses=1]
br label %bb14
; CHECK: bb14:
; CHECK-NEXT: store i8 undef, i8* [[SCEVGEP]]
; CHECK-NEXT: %t6 = load float** undef
; Fold %t3's add within the address.
; CHECK-NEXT: [[SCEVGEP1:%[^ ]+]] = getelementptr float* %t6, i64 4
; CHECK-NEXT: [[SCEVGEP2:%[^ ]+]] = bitcast float* [[SCEVGEP1]] to i8*
; Use the induction variable (%t4) to access the right element
; CHECK-NEXT: [[ADDRESS:%[^ ]+]] = getelementptr i8* [[SCEVGEP2]], i64 %t4
; CHECK-NEXT: store i8 undef, i8* [[ADDRESS]]
; CHECK-NEXT: br label %bb14
bb14: ; preds = %bb14, %bb10
%t2 = getelementptr inbounds i8* undef, i64 %t4 ; <i8*> [#uses=1]
store i8 undef, i8* %t2
%t6 = load float** undef
%t8 = bitcast float* %t6 to i8* ; <i8*> [#uses=1]
%t9 = getelementptr inbounds i8* %t8, i64 %t3 ; <i8*> [#uses=1]
store i8 undef, i8* %t9
br label %bb14
}
define fastcc void @TransformLine() nounwind {
; CHECK: @TransformLine
bb:
br label %loop0
; CHECK: loop0:
; Induction variable is initialized to -2.
; CHECK-NEXT: [[PHIIV:%[^ ]+]] = phi i32 [ [[IVNEXT:%[^ ]+]], %loop0 ], [ -2, %bb ]
; CHECK-NEXT: [[IVNEXT]] = add i32 [[PHIIV]], 1
; CHECK-NEXT: br i1 false, label %loop0, label %bb0
loop0: ; preds = %loop0, %bb
%i0 = phi i32 [ %i0.next, %loop0 ], [ 0, %bb ] ; <i32> [#uses=2]
%i0.next = add i32 %i0, 1 ; <i32> [#uses=1]
br i1 false, label %loop0, label %bb0
bb0: ; preds = %loop0
br label %loop1
; CHECK: loop1:
; CHECK-NEXT: %i1 = phi i32 [ 0, %bb0 ], [ %i1.next, %bb5 ]
; IVNEXT covers the uses of %i0 and %t0.
; Therefore, %t0 has been removed.
; The critical edge has been split.
; CHECK-NEXT: br i1 false, label %bb2, label %[[LOOP1BB6:.+]]
loop1: ; preds = %bb5, %bb0
%i1 = phi i32 [ 0, %bb0 ], [ %i1.next, %bb5 ] ; <i32> [#uses=4]
%t0 = add i32 %i0, %i1 ; <i32> [#uses=1]
br i1 false, label %bb2, label %bb6
; CHECK: bb2:
; Critical edge split.
; CHECK-NEXT: br i1 true, label %[[BB2BB6:[^,]+]], label %bb5
bb2: ; preds = %loop1
br i1 true, label %bb6, label %bb5
; CHECK: bb5:
; CHECK-NEXT: %i1.next = add i32 %i1, 1
; CHECK-NEXT: br i1 true, label %[[BB5BB6:[^,]+]], label %loop1
bb5: ; preds = %bb2
%i1.next = add i32 %i1, 1 ; <i32> [#uses=1]
br i1 true, label %bb6, label %loop1
; bb5 to bb6 split basic block.
; CHECK: [[BB5BB6]]:
; CHECK-NEXT: [[INITIALVAL:%[^ ]+]] = add i32 [[IVNEXT]], %i1.next
; CHECK-NEXT: br label %[[SPLITTOBB6:.+]]
; bb2 to bb6 split basic block.
; CHECK: [[BB2BB6]]:
; CHECK-NEXT: br label %[[SPLITTOBB6]]
; Split basic blocks to bb6.
; CHECK: [[SPLITTOBB6]]:
; CHECK-NEXT: [[INITP8:%[^ ]+]] = phi i32 [ [[INITIALVAL]], %[[BB5BB6]] ], [ undef, %[[BB2BB6]] ]
; CHECK-NEXT: [[INITP9:%[^ ]+]] = phi i32 [ undef, %[[BB5BB6]] ], [ %i1, %[[BB2BB6]] ]
; CHECK-NEXT: br label %bb6
; CHECK: [[LOOP1BB6]]:
; CHECK-NEXT: br label %bb6
; CHECK: bb6:
; CHECK-NEXT: %p8 = phi i32 [ undef, %[[LOOP1BB6]] ], [ [[INITP8]], %[[SPLITTOBB6]] ]
; CHECK-NEXT: %p9 = phi i32 [ %i1, %[[LOOP1BB6]] ], [ [[INITP9]], %[[SPLITTOBB6]] ]
; CHECK-NEXT: unreachable
bb6: ; preds = %bb5, %bb2, %loop1
%p8 = phi i32 [ %t0, %bb5 ], [ undef, %loop1 ], [ undef, %bb2 ] ; <i32> [#uses=0]
%p9 = phi i32 [ undef, %bb5 ], [ %i1, %loop1 ], [ %i1, %bb2 ] ; <i32> [#uses=0]
unreachable
}