1971bc46fSRoman Lebedev; RUN: opt -passes=loop-load-elim -S < %s | FileCheck %s 2cee313d2SEric Christopher 3cee313d2SEric Christopher; Simple st->ld forwarding derived from a lexical backward dep. 4cee313d2SEric Christopher; 5cee313d2SEric Christopher; for (unsigned i = 0; i < 100; i++) 6cee313d2SEric Christopher; A[i+1] = A[i] + B[i]; 7cee313d2SEric Christopher 8cee313d2SEric Christophertarget datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" 9cee313d2SEric Christopher 10055fb779SNikita Popovdefine void @f(ptr noalias nocapture %A, ptr noalias nocapture readonly %B, i64 %N) { 11cee313d2SEric Christopherentry: 12055fb779SNikita Popov; CHECK: %load_initial = load i32, ptr %A 13cee313d2SEric Christopher br label %for.body 14cee313d2SEric Christopher 15cee313d2SEric Christopherfor.body: ; preds = %for.body, %entry 16cee313d2SEric Christopher; CHECK: %store_forwarded = phi i32 [ %load_initial, %entry ], [ %add, %for.body ] 17cee313d2SEric Christopher %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ] 18055fb779SNikita Popov %arrayidx = getelementptr inbounds i32, ptr %A, i64 %indvars.iv 19055fb779SNikita Popov %load = load i32, ptr %arrayidx, align 4 20055fb779SNikita Popov %arrayidx2 = getelementptr inbounds i32, ptr %B, i64 %indvars.iv 21055fb779SNikita Popov %load_1 = load i32, ptr %arrayidx2, align 4 22cee313d2SEric Christopher; CHECK: %add = add i32 %load_1, %store_forwarded 23cee313d2SEric Christopher %add = add i32 %load_1, %load 24cee313d2SEric Christopher %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1 25055fb779SNikita Popov %arrayidx_next = getelementptr inbounds i32, ptr %A, i64 %indvars.iv.next 26055fb779SNikita Popov store i32 %add, ptr %arrayidx_next, align 4 27cee313d2SEric Christopher %exitcond = icmp eq i64 %indvars.iv.next, %N 28cee313d2SEric Christopher br i1 %exitcond, label %for.end, label %for.body 29cee313d2SEric Christopher 30cee313d2SEric Christopherfor.end: ; preds = %for.body 31cee313d2SEric Christopher ret void 32cee313d2SEric Christopher} 33*50dfc9e3SIgor Kirillov 34*50dfc9e3SIgor Kirillov; Same but loop is descending. 35*50dfc9e3SIgor Kirillov; 36*50dfc9e3SIgor Kirillov; for (unsigned i = N; i > 0; i--) 37*50dfc9e3SIgor Kirillov; A[i-1] = A[i] + B[i]; 38*50dfc9e3SIgor Kirillovdefine void @g(ptr noalias nocapture %A, ptr noalias nocapture readonly %B, i64 %N) { 39*50dfc9e3SIgor Kirilloventry: 40*50dfc9e3SIgor Kirillov; CHECK: %0 = shl i64 %N, 2 41*50dfc9e3SIgor Kirillov; CHECK: %scevgep = getelementptr i8, ptr %A, i64 %0 42*50dfc9e3SIgor Kirillov; CHECK: %load_initial = load i32, ptr %scevgep, align 4 43*50dfc9e3SIgor Kirillov br label %for.body 44*50dfc9e3SIgor Kirillov 45*50dfc9e3SIgor Kirillovfor.body: ; preds = %for.body, %entry 46*50dfc9e3SIgor Kirillov; CHECK: %store_forwarded = phi i32 [ %load_initial, %entry ], [ %add, %for.body ] 47*50dfc9e3SIgor Kirillov %i.09 = phi i64 [ %sub, %for.body ], [ %N, %entry ] 48*50dfc9e3SIgor Kirillov %arrayidx = getelementptr inbounds i32, ptr %A, i64 %i.09 49*50dfc9e3SIgor Kirillov %load = load i32, ptr %arrayidx, align 4 50*50dfc9e3SIgor Kirillov %arrayidx1 = getelementptr inbounds i32, ptr %B, i64 %i.09 51*50dfc9e3SIgor Kirillov %load_1 = load i32, ptr %arrayidx1, align 4 52*50dfc9e3SIgor Kirillov; CHECK: %add = add i32 %load_1, %store_forwarded 53*50dfc9e3SIgor Kirillov %add = add i32 %load_1, %load 54*50dfc9e3SIgor Kirillov %sub = add i64 %i.09, -1 55*50dfc9e3SIgor Kirillov %arrayidx2 = getelementptr inbounds i32, ptr %A, i64 %sub 56*50dfc9e3SIgor Kirillov store i32 %add, ptr %arrayidx2, align 4 57*50dfc9e3SIgor Kirillov %cmp.not = icmp eq i64 %sub, 0 58*50dfc9e3SIgor Kirillov br i1 %cmp.not, label %for.end, label %for.body 59*50dfc9e3SIgor Kirillov 60*50dfc9e3SIgor Kirillovfor.end: ; preds = %for.body 61*50dfc9e3SIgor Kirillov ret void 62*50dfc9e3SIgor Kirillov} 63*50dfc9e3SIgor Kirillov 64