small-constant.ll
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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s -mtriple=aarch64-unknown-unknown | FileCheck %s
; Test LSR for giving small constants, which get re-associated as unfolded
; offset, a chance to get combined with loop-invariant registers (same as
; large constants which do not fit as add immediate operands). LSR
; favors here to bump the base pointer outside the loop.
; float test(float *arr, long long start, float threshold) {
; for (long long i = start; i != 0; ++i) {
; float x = arr[i + 7];
; if (x > threshold)
; return x;
; }
; return -7;
; }
define float @test1(float* nocapture readonly %arr, i64 %start, float %threshold) {
; CHECK-LABEL: test1:
; CHECK: // %bb.0: // %entry
; CHECK-NEXT: cbz x1, .LBB0_4
; CHECK-NEXT: // %bb.1: // %for.body.preheader
; CHECK-NEXT: add x8, x0, #28 // =28
; CHECK-NEXT: .LBB0_2: // %for.body
; CHECK-NEXT: // =>This Inner Loop Header: Depth=1
; CHECK-NEXT: ldr s1, [x8, x1, lsl #2]
; CHECK-NEXT: fcmp s1, s0
; CHECK-NEXT: b.gt .LBB0_5
; CHECK-NEXT: // %bb.3: // %for.cond
; CHECK-NEXT: // in Loop: Header=BB0_2 Depth=1
; CHECK-NEXT: add x1, x1, #1 // =1
; CHECK-NEXT: cbnz x1, .LBB0_2
; CHECK-NEXT: .LBB0_4:
; CHECK-NEXT: fmov s0, #-7.00000000
; CHECK-NEXT: ret
; CHECK-NEXT: .LBB0_5: // %cleanup2
; CHECK-NEXT: mov v0.16b, v1.16b
; CHECK-NEXT: ret
entry:
%cmp11 = icmp eq i64 %start, 0
br i1 %cmp11, label %cleanup2, label %for.body
for.cond: ; preds = %for.body
%cmp = icmp eq i64 %inc, 0
br i1 %cmp, label %cleanup2, label %for.body
for.body: ; preds = %entry, %for.cond
%i.012 = phi i64 [ %inc, %for.cond ], [ %start, %entry ]
%add = add nsw i64 %i.012, 7
%arrayidx = getelementptr inbounds float, float* %arr, i64 %add
%0 = load float, float* %arrayidx, align 4
%cmp1 = fcmp ogt float %0, %threshold
%inc = add nsw i64 %i.012, 1
br i1 %cmp1, label %cleanup2, label %for.cond
cleanup2: ; preds = %for.cond, %for.body, %entry
%1 = phi float [ -7.000000e+00, %entry ], [ %0, %for.body ], [ -7.000000e+00, %for.cond ]
ret float %1
}
; Same as test1, except i has another use:
; if (x > threshold) ---> if (x > threshold + i)
define float @test2(float* nocapture readonly %arr, i64 %start, float %threshold) {
; CHECK-LABEL: test2:
; CHECK: // %bb.0: // %entry
; CHECK-NEXT: cbz x1, .LBB1_4
; CHECK-NEXT: // %bb.1: // %for.body.preheader
; CHECK-NEXT: add x8, x0, #28 // =28
; CHECK-NEXT: .LBB1_2: // %for.body
; CHECK-NEXT: // =>This Inner Loop Header: Depth=1
; CHECK-NEXT: ldr s1, [x8, x1, lsl #2]
; CHECK-NEXT: scvtf s2, x1
; CHECK-NEXT: fadd s2, s2, s0
; CHECK-NEXT: fcmp s1, s2
; CHECK-NEXT: b.gt .LBB1_5
; CHECK-NEXT: // %bb.3: // %for.cond
; CHECK-NEXT: // in Loop: Header=BB1_2 Depth=1
; CHECK-NEXT: add x1, x1, #1 // =1
; CHECK-NEXT: cbnz x1, .LBB1_2
; CHECK-NEXT: .LBB1_4:
; CHECK-NEXT: fmov s0, #-7.00000000
; CHECK-NEXT: ret
; CHECK-NEXT: .LBB1_5: // %cleanup4
; CHECK-NEXT: mov v0.16b, v1.16b
; CHECK-NEXT: ret
entry:
%cmp14 = icmp eq i64 %start, 0
br i1 %cmp14, label %cleanup4, label %for.body
for.cond: ; preds = %for.body
%cmp = icmp eq i64 %inc, 0
br i1 %cmp, label %cleanup4, label %for.body
for.body: ; preds = %entry, %for.cond
%i.015 = phi i64 [ %inc, %for.cond ], [ %start, %entry ]
%add = add nsw i64 %i.015, 7
%arrayidx = getelementptr inbounds float, float* %arr, i64 %add
%0 = load float, float* %arrayidx, align 4
%conv = sitofp i64 %i.015 to float
%add1 = fadd float %conv, %threshold
%cmp2 = fcmp ogt float %0, %add1
%inc = add nsw i64 %i.015, 1
br i1 %cmp2, label %cleanup4, label %for.cond
cleanup4: ; preds = %for.cond, %for.body, %entry
%1 = phi float [ -7.000000e+00, %entry ], [ %0, %for.body ], [ -7.000000e+00, %for.cond ]
ret float %1
}