llvm-6502/test/Transforms/LoopVectorize/hoist-loads.ll
Arnold Schwaighofer 1386692ef6 LoopVectorize: Hoist conditional loads if possible
InstCombine can be uncooperative to vectorization and sink loads into
conditional blocks. This prevents vectorization.

Undo this optimization if there are unconditional memory accesses to the same
addresses in the loop.

radar://13815763

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181860 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-15 01:44:30 +00:00

70 lines
2.3 KiB
LLVM

; RUN: opt -loop-vectorize -force-vector-width=2 -force-vector-unroll=1 -S < %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"
@A = common global [1024 x float] zeroinitializer, align 16
@B = common global [1024 x float] zeroinitializer, align 16
; Make sure we can vectorize in the presence of hoistable conditional loads.
; CHECK: hoist_cond_load
; CHECK: load <2 x float>
define void @hoist_cond_load() {
entry:
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %if.end9 ]
%arrayidx = getelementptr inbounds [1024 x float]* @A, i64 0, i64 %indvars.iv
%arrayidx2 = getelementptr inbounds [1024 x float]* @B, i64 0, i64 %indvars.iv
%0 = load float* %arrayidx2, align 4
%cmp3 = fcmp oeq float %0, 0.000000e+00
br i1 %cmp3, label %if.end9, label %if.else
if.else:
%1 = load float* %arrayidx, align 4
br label %if.end9
if.end9:
%tmp.0 = phi float [ %1, %if.else ], [ 0.000000e+00, %for.body ]
store float %tmp.0, float* %arrayidx, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp ne i32 %lftr.wideiv, 1024
br i1 %exitcond, label %for.body, label %for.end
for.end:
ret void
}
; However, we can't hoist loads whose address we have not seen unconditionally
; accessed.
; CHECK: dont_hoist_cond_load
; CHECK-NOT: load <2 x float>
define void @dont_hoist_cond_load() {
entry:
br label %for.body
for.body:
%indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %if.end9 ]
%arrayidx = getelementptr inbounds [1024 x float]* @A, i64 0, i64 %indvars.iv
%arrayidx2 = getelementptr inbounds [1024 x float]* @B, i64 0, i64 %indvars.iv
%0 = load float* %arrayidx2, align 4
%cmp3 = fcmp oeq float %0, 0.000000e+00
br i1 %cmp3, label %if.end9, label %if.else
if.else:
%1 = load float* %arrayidx, align 4
br label %if.end9
if.end9:
%tmp.0 = phi float [ %1, %if.else ], [ 0.000000e+00, %for.body ]
store float %tmp.0, float* %arrayidx2, align 4
%indvars.iv.next = add i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv.next to i32
%exitcond = icmp ne i32 %lftr.wideiv, 1024
br i1 %exitcond, label %for.body, label %for.end
for.end:
ret void
}