llvm-6502/test/Transforms/InstMerge/ld_hoist1.ll
Elena Demikhovsky 01d89eee39 Use Alias Analysis to hoist 2 loads from diamond to the common predecessor basic block.
Alias Analysis allows to detect real barriers for load hoisting.

Review in http://reviews.llvm.org/D5991



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221091 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-02 08:03:05 +00:00

65 lines
2.5 KiB
LLVM

; Test load hoist
; RUN: opt -basicaa -memdep -mldst-motion -S < %s | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc_linux"
; Function Attrs: nounwind uwtable
define float* @foo(i32* noalias nocapture readonly %in, float* noalias %out, i32 %size, i32* nocapture readonly %trigger) {
entry:
%cmp11 = icmp eq i32 %size, 0
br i1 %cmp11, label %for.end, label %for.body.lr.ph
for.body.lr.ph: ; preds = %entry
%0 = add i32 %size, -1
br label %for.body
; CHECK-LABEL: for.body
; CHECK: load
; CHECK: %2 = getelementptr inbounds i32* %in, i64 %indvars.iv
; CHECK: %3 = load i32* %2, align 4
for.body: ; preds = %for.body.lr.ph, %for.inc
%indvars.iv = phi i64 [ 0, %for.body.lr.ph ], [ %indvars.iv.next, %for.inc ]
%arrayidx = getelementptr inbounds i32* %trigger, i64 %indvars.iv
%1 = load i32* %arrayidx, align 4
%cmp1 = icmp sgt i32 %1, 0
br i1 %cmp1, label %if.then, label %if.else
; CHECK-LABEL: if.then
if.then: ; preds = %for.body
; This load should be hoisted
%arrayidx3 = getelementptr inbounds i32* %in, i64 %indvars.iv
%2 = load i32* %arrayidx3, align 4
%conv = sitofp i32 %2 to float
%add = fadd float %conv, 5.000000e-01
%arrayidx5 = getelementptr inbounds float* %out, i64 %indvars.iv
store float %add, float* %arrayidx5, align 4
br label %for.inc
if.else: ; preds = %for.body
%arrayidx7 = getelementptr inbounds float* %out, i64 %indvars.iv
%3 = load float* %arrayidx7, align 4
%div = fdiv float %3, 3.000000e+00
store float %div, float* %arrayidx7, align 4
; This load should be hoisted in spite of store
%arrayidx9 = getelementptr inbounds i32* %in, i64 %indvars.iv
%4 = load i32* %arrayidx9, align 4
%conv10 = sitofp i32 %4 to float
%add13 = fadd float %div, %conv10
store float %add13, float* %arrayidx7, align 4
br label %for.inc
for.inc: ; preds = %if.then, %if.else
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%lftr.wideiv = trunc i64 %indvars.iv to i32
%exitcond = icmp ne i32 %lftr.wideiv, %0
br i1 %exitcond, label %for.body, label %for.cond.for.end_crit_edge
for.cond.for.end_crit_edge: ; preds = %for.inc
br label %for.end
for.end: ; preds = %entry, %for.cond.for.end_crit_edge
ret float* %out
}