7b88bab386
LSR reassociates constants as unfolded offsets when the constants fit as immediate add operands, which currently prevents such constants from being combined later with loop invariant registers. This patch modifies GenerateCombinations() to generate a second formula which includes the unfolded offset in the combined loop-invariant register. This commit fixes a bug in the original patch (committed at r345114, reverted at r345123). Differential Revision: https://reviews.llvm.org/D51861 llvm-svn: 346390
117 lines
4.2 KiB
LLVM
117 lines
4.2 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc < %s -mtriple=aarch64-unknown-unknown | FileCheck %s
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; Test LSR for giving small constants, which get re-associated as unfolded
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; offset, a chance to get combined with loop-invariant registers (same as
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; large constants which do not fit as add immediate operands). LSR
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; favors here to bump the base pointer outside the loop.
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; float test(float *arr, long long start, float threshold) {
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; for (long long i = start; i != 0; ++i) {
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; float x = arr[i + 7];
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; if (x > threshold)
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; return x;
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; }
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; return -7;
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; }
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define float @test1(float* nocapture readonly %arr, i64 %start, float %threshold) {
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; CHECK-LABEL: test1:
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; CHECK: // %bb.0: // %entry
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; CHECK-NEXT: fmov s2, #-7.00000000
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; CHECK-NEXT: cbz x1, .LBB0_5
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; CHECK-NEXT: // %bb.1: // %for.body.preheader
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; CHECK-NEXT: add x8, x0, #28 // =28
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; CHECK-NEXT: .LBB0_2: // %for.body
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; CHECK-NEXT: // =>This Inner Loop Header: Depth=1
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; CHECK-NEXT: ldr s1, [x8, x1, lsl #2]
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; CHECK-NEXT: fcmp s1, s0
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; CHECK-NEXT: b.gt .LBB0_6
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; CHECK-NEXT: // %bb.3: // %for.cond
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; CHECK-NEXT: // in Loop: Header=BB0_2 Depth=1
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; CHECK-NEXT: add x1, x1, #1 // =1
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; CHECK-NEXT: cbnz x1, .LBB0_2
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; CHECK-NEXT: // %bb.4:
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; CHECK-NEXT: mov v0.16b, v2.16b
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; CHECK-NEXT: ret
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; CHECK-NEXT: .LBB0_5:
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; CHECK-NEXT: mov v0.16b, v2.16b
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; CHECK-NEXT: ret
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; CHECK-NEXT: .LBB0_6: // %cleanup2
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; CHECK-NEXT: mov v0.16b, v1.16b
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; CHECK-NEXT: ret
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entry:
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%cmp11 = icmp eq i64 %start, 0
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br i1 %cmp11, label %cleanup2, label %for.body
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for.cond: ; preds = %for.body
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%cmp = icmp eq i64 %inc, 0
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br i1 %cmp, label %cleanup2, label %for.body
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for.body: ; preds = %entry, %for.cond
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%i.012 = phi i64 [ %inc, %for.cond ], [ %start, %entry ]
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%add = add nsw i64 %i.012, 7
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%arrayidx = getelementptr inbounds float, float* %arr, i64 %add
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%0 = load float, float* %arrayidx, align 4
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%cmp1 = fcmp ogt float %0, %threshold
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%inc = add nsw i64 %i.012, 1
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br i1 %cmp1, label %cleanup2, label %for.cond
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cleanup2: ; preds = %for.cond, %for.body, %entry
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%1 = phi float [ -7.000000e+00, %entry ], [ %0, %for.body ], [ -7.000000e+00, %for.cond ]
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ret float %1
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}
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; Same as test1, except i has another use:
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; if (x > threshold) ---> if (x > threshold + i)
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define float @test2(float* nocapture readonly %arr, i64 %start, float %threshold) {
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; CHECK-LABEL: test2:
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; CHECK: // %bb.0: // %entry
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; CHECK-NEXT: fmov s2, #-7.00000000
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; CHECK-NEXT: cbz x1, .LBB1_5
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; CHECK-NEXT: // %bb.1: // %for.body.preheader
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; CHECK-NEXT: add x8, x0, #28 // =28
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; CHECK-NEXT: .LBB1_2: // %for.body
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; CHECK-NEXT: // =>This Inner Loop Header: Depth=1
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; CHECK-NEXT: ldr s1, [x8, x1, lsl #2]
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; CHECK-NEXT: scvtf s3, x1
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; CHECK-NEXT: fadd s3, s3, s0
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; CHECK-NEXT: fcmp s1, s3
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; CHECK-NEXT: b.gt .LBB1_6
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; CHECK-NEXT: // %bb.3: // %for.cond
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; CHECK-NEXT: // in Loop: Header=BB1_2 Depth=1
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; CHECK-NEXT: add x1, x1, #1 // =1
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; CHECK-NEXT: cbnz x1, .LBB1_2
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; CHECK-NEXT: // %bb.4:
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; CHECK-NEXT: mov v0.16b, v2.16b
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; CHECK-NEXT: ret
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; CHECK-NEXT: .LBB1_5:
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; CHECK-NEXT: mov v0.16b, v2.16b
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; CHECK-NEXT: ret
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; CHECK-NEXT: .LBB1_6: // %cleanup4
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; CHECK-NEXT: mov v0.16b, v1.16b
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; CHECK-NEXT: ret
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entry:
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%cmp14 = icmp eq i64 %start, 0
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br i1 %cmp14, label %cleanup4, label %for.body
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for.cond: ; preds = %for.body
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%cmp = icmp eq i64 %inc, 0
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br i1 %cmp, label %cleanup4, label %for.body
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for.body: ; preds = %entry, %for.cond
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%i.015 = phi i64 [ %inc, %for.cond ], [ %start, %entry ]
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%add = add nsw i64 %i.015, 7
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%arrayidx = getelementptr inbounds float, float* %arr, i64 %add
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%0 = load float, float* %arrayidx, align 4
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%conv = sitofp i64 %i.015 to float
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%add1 = fadd float %conv, %threshold
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%cmp2 = fcmp ogt float %0, %add1
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%inc = add nsw i64 %i.015, 1
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br i1 %cmp2, label %cleanup4, label %for.cond
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cleanup4: ; preds = %for.cond, %for.body, %entry
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%1 = phi float [ -7.000000e+00, %entry ], [ %0, %for.body ], [ -7.000000e+00, %for.cond ]
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ret float %1
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}
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