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llvm-mirror/test/Transforms/LoopVectorize/reverse_induction.ll
James Molloy a4cf659555 [LV] Switch to using canonical induction variables.
Vectorized loops only ever have one induction variable. All induction PHIs from the scalar loop are rewritten to be in terms of this single indvar.

We were trying very hard to pick an indvar that already existed, even if that indvar wasn't canonical (didn't start at zero). But trying so hard is really fruitless - creating a new, canonical, indvar only results in one extra add in the worst case and that add is trivially easy to push through the PHI out of the loop by instcombine.

If we try and be less clever here and instead let instcombine clean up our mess (as we do in many other places in LV), we can remove unneeded complexity.

llvm-svn: 246630
2015-09-02 10:14:54 +00:00

146 lines
4.8 KiB
LLVM

; RUN: opt < %s -loop-vectorize -force-vector-interleave=2 -force-vector-width=4 -S | FileCheck %s
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-S128"
; Make sure consecutive vector generates correct negative indices.
; PR15882
; CHECK-LABEL: @reverse_induction_i64(
; CHECK: add <4 x i64> %[[SPLAT:.*]], <i64 0, i64 -1, i64 -2, i64 -3>
; CHECK: add <4 x i64> %[[SPLAT]], <i64 -4, i64 -5, i64 -6, i64 -7>
define i32 @reverse_induction_i64(i64 %startval, i32 * %ptr) {
entry:
br label %for.body
for.body:
%add.i7 = phi i64 [ %startval, %entry ], [ %add.i, %for.body ]
%i.06 = phi i32 [ 0, %entry ], [ %inc4, %for.body ]
%redux5 = phi i32 [ 0, %entry ], [ %inc.redux, %for.body ]
%add.i = add i64 %add.i7, -1
%kind_.i = getelementptr inbounds i32, i32* %ptr, i64 %add.i
%tmp.i1 = load i32, i32* %kind_.i, align 4
%inc.redux = add i32 %tmp.i1, %redux5
%inc4 = add i32 %i.06, 1
%exitcond = icmp ne i32 %inc4, 1024
br i1 %exitcond, label %for.body, label %loopend
loopend:
ret i32 %inc.redux
}
; CHECK-LABEL: @reverse_induction_i128(
; CHECK: add <4 x i128> %[[SPLAT:.*]], <i128 0, i128 -1, i128 -2, i128 -3>
; CHECK: add <4 x i128> %[[SPLAT]], <i128 -4, i128 -5, i128 -6, i128 -7>
define i32 @reverse_induction_i128(i128 %startval, i32 * %ptr) {
entry:
br label %for.body
for.body:
%add.i7 = phi i128 [ %startval, %entry ], [ %add.i, %for.body ]
%i.06 = phi i32 [ 0, %entry ], [ %inc4, %for.body ]
%redux5 = phi i32 [ 0, %entry ], [ %inc.redux, %for.body ]
%add.i = add i128 %add.i7, -1
%kind_.i = getelementptr inbounds i32, i32* %ptr, i128 %add.i
%tmp.i1 = load i32, i32* %kind_.i, align 4
%inc.redux = add i32 %tmp.i1, %redux5
%inc4 = add i32 %i.06, 1
%exitcond = icmp ne i32 %inc4, 1024
br i1 %exitcond, label %for.body, label %loopend
loopend:
ret i32 %inc.redux
}
; CHECK-LABEL: @reverse_induction_i16(
; CHECK: add <4 x i16> %[[SPLAT:.*]], <i16 0, i16 -1, i16 -2, i16 -3>
; CHECK: add <4 x i16> %[[SPLAT]], <i16 -4, i16 -5, i16 -6, i16 -7>
define i32 @reverse_induction_i16(i16 %startval, i32 * %ptr) {
entry:
br label %for.body
for.body:
%add.i7 = phi i16 [ %startval, %entry ], [ %add.i, %for.body ]
%i.06 = phi i32 [ 0, %entry ], [ %inc4, %for.body ]
%redux5 = phi i32 [ 0, %entry ], [ %inc.redux, %for.body ]
%add.i = add i16 %add.i7, -1
%kind_.i = getelementptr inbounds i32, i32* %ptr, i16 %add.i
%tmp.i1 = load i32, i32* %kind_.i, align 4
%inc.redux = add i32 %tmp.i1, %redux5
%inc4 = add i32 %i.06, 1
%exitcond = icmp ne i32 %inc4, 1024
br i1 %exitcond, label %for.body, label %loopend
loopend:
ret i32 %inc.redux
}
@a = common global [1024 x i32] zeroinitializer, align 16
; We incorrectly transformed this loop into an empty one because we left the
; induction variable in i8 type and truncated the exit value 1024 to 0.
; int a[1024];
;
; void fail() {
; int reverse_induction = 1023;
; unsigned char forward_induction = 0;
; while ((reverse_induction) >= 0) {
; forward_induction++;
; a[reverse_induction] = forward_induction;
; --reverse_induction;
; }
; }
; CHECK-LABEL: @reverse_forward_induction_i64_i8(
; CHECK: vector.body
; CHECK: %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
; CHECK: %offset.idx = sub i64 1023, %index
; CHECK: trunc i64 %index to i8
define void @reverse_forward_induction_i64_i8() {
entry:
br label %while.body
while.body:
%indvars.iv = phi i64 [ 1023, %entry ], [ %indvars.iv.next, %while.body ]
%forward_induction.05 = phi i8 [ 0, %entry ], [ %inc, %while.body ]
%inc = add i8 %forward_induction.05, 1
%conv = zext i8 %inc to i32
%arrayidx = getelementptr inbounds [1024 x i32], [1024 x i32]* @a, i64 0, i64 %indvars.iv
store i32 %conv, i32* %arrayidx, align 4
%indvars.iv.next = add i64 %indvars.iv, -1
%0 = trunc i64 %indvars.iv to i32
%cmp = icmp sgt i32 %0, 0
br i1 %cmp, label %while.body, label %while.end
while.end:
ret void
}
; CHECK-LABEL: @reverse_forward_induction_i64_i8_signed(
; CHECK: vector.body:
; CHECK: %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
; CHECK: %offset.idx = sub i64 1023, %index
define void @reverse_forward_induction_i64_i8_signed() {
entry:
br label %while.body
while.body:
%indvars.iv = phi i64 [ 1023, %entry ], [ %indvars.iv.next, %while.body ]
%forward_induction.05 = phi i8 [ -127, %entry ], [ %inc, %while.body ]
%inc = add i8 %forward_induction.05, 1
%conv = sext i8 %inc to i32
%arrayidx = getelementptr inbounds [1024 x i32], [1024 x i32]* @a, i64 0, i64 %indvars.iv
store i32 %conv, i32* %arrayidx, align 4
%indvars.iv.next = add i64 %indvars.iv, -1
%0 = trunc i64 %indvars.iv to i32
%cmp = icmp sgt i32 %0, 0
br i1 %cmp, label %while.body, label %while.end
while.end:
ret void
}