2fee8dd621
When enabling freeze-loop-unswitch-cond the inserted freeze instruction may block unswitching of parent loops if they get inserted in a block in the parent loop (as the llvm::Loop-based invariance check only checks whether an instruction is in a loop block or not). In the optimization pipeline, LICM is responsible to hoist out loop invariant instructions to enable further unswitching. Also run LICM for nested unswitching tests in preparation for flipping the default of freeze-loop-unswitch-cond. Reviewed By: nikic Differential Revision: https://reviews.llvm.org/D124251
150 lines
5.7 KiB
LLVM
150 lines
5.7 KiB
LLVM
;
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; There should be just a single copy of each loop when strictest mutiplier
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; candidates formula (unscaled candidates == 0) is enforced:
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; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
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; RUN: -unswitch-num-initial-unscaled-candidates=0 -unswitch-siblings-toplevel-div=1 \
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; RUN: -passes='loop-mssa(simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | FileCheck %s --check-prefixes=LOOP1
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;
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; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
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; RUN: -unswitch-num-initial-unscaled-candidates=0 -unswitch-siblings-toplevel-div=16 \
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; RUN: -passes='loop(simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | FileCheck %s --check-prefixes=LOOP1
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;
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; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
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; RUN: -unswitch-num-initial-unscaled-candidates=0 -unswitch-siblings-toplevel-div=1 \
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; RUN: -passes='loop-mssa(simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | FileCheck %s --check-prefixes=LOOP1
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;
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; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
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; RUN: -unswitch-num-initial-unscaled-candidates=0 -unswitch-siblings-toplevel-div=16 \
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; RUN: -passes='loop-mssa(simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | FileCheck %s --check-prefixes=LOOP1
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;
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; When we relax the candidates part of a multiplier formula
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; (unscaled candidates == 4) we start getting some unswitches,
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; which leads to siblings multiplier kicking in.
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;
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; The tests below also run licm, because it is needed to hoist out
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; loop-invariant freeze instructions, which otherwise may block further
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; unswitching.
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;
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; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
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; RUN: -unswitch-num-initial-unscaled-candidates=4 -unswitch-siblings-toplevel-div=1 \
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; RUN: -passes='loop-mssa(licm,simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | \
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; RUN: sort -b -k 1 | FileCheck %s --check-prefixes=LOOP-UNSCALE4-DIV1
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;
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; NB: sort -b is essential here and below, otherwise blanks might lead to different
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; order depending on locale.
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;
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; RUN: opt < %s -enable-unswitch-cost-multiplier=true \
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; RUN: -unswitch-num-initial-unscaled-candidates=4 -unswitch-siblings-toplevel-div=2 \
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; RUN: -passes='loop-mssa(licm,simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | \
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; RUN: sort -b -k 1 | FileCheck %s --check-prefixes=LOOP-UNSCALE4-DIV2
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;
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; Get
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; 2^(num conds) == 2^5 = 32
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; loop nests when cost multiplier is disabled:
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;
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; RUN: opt < %s -enable-unswitch-cost-multiplier=false \
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; RUN: -passes='loop-mssa(licm,simple-loop-unswitch<nontrivial>),print<loops>' -disable-output 2>&1 | \
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; RUN: sort -b -k 1 | FileCheck %s --check-prefixes=LOOP32
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;
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; Single loop nest, not unswitched
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; LOOP1: Loop at depth 1 containing:
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; LOOP1: Loop at depth 2 containing:
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; LOOP1: Loop at depth 3 containing:
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; LOOP1-NOT: Loop at depth {{[0-9]+}} containing:
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;
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; Half unswitched loop nests, with unscaled4 and div1 it gets less depth1 loops unswitched
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; since they have more cost.
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; LOOP-UNSCALE4-DIV1-COUNT-6: Loop at depth 1 containing:
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; LOOP-UNSCALE4-DIV1-COUNT-19: Loop at depth 2 containing:
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; LOOP-UNSCALE4-DIV1-COUNT-29: Loop at depth 3 containing:
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; LOOP-UNSCALE4-DIV1-NOT: Loop at depth {{[0-9]+}} containing:
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;
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; Half unswitched loop nests, with unscaled4 and div2 it gets more depth1 loops unswitched
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; as div2 kicks in.
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; LOOP-UNSCALE4-DIV2-COUNT-11: Loop at depth 1 containing:
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; LOOP-UNSCALE4-DIV2-COUNT-22: Loop at depth 2 containing:
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; LOOP-UNSCALE4-DIV2-COUNT-29: Loop at depth 3 containing:
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; LOOP-UNSCALE4-DIV2-NOT: Loop at depth {{[0-9]+}} containing:
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;
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; 32 loop nests, fully unswitched
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; LOOP32-COUNT-32: Loop at depth 1 containing:
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; LOOP32-COUNT-32: Loop at depth 2 containing:
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; LOOP32-COUNT-32: Loop at depth 3 containing:
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; LOOP32-NOT: Loop at depth {{[0-9]+}} containing:
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declare void @bar()
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define void @loop_nested3_conds5(i32* %addr, i1 %c1, i1 %c2, i1 %c3, i1 %c4, i1 %c5) {
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entry:
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%addr1 = getelementptr i32, i32* %addr, i64 0
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%addr2 = getelementptr i32, i32* %addr, i64 1
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%addr3 = getelementptr i32, i32* %addr, i64 2
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br label %outer
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outer:
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%iv1 = phi i32 [0, %entry], [%iv1.next, %outer_latch]
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%iv1.next = add i32 %iv1, 1
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;; skip nontrivial unswitch
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call void @bar()
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br label %middle
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middle:
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%iv2 = phi i32 [0, %outer], [%iv2.next, %middle_latch]
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%iv2.next = add i32 %iv2, 1
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;; skip nontrivial unswitch
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call void @bar()
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br label %loop
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loop:
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%iv3 = phi i32 [0, %middle], [%iv3.next, %loop_latch]
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%iv3.next = add i32 %iv3, 1
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;; skip nontrivial unswitch
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call void @bar()
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br i1 %c1, label %loop_next1_left, label %loop_next1_right
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loop_next1_left:
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br label %loop_next1
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loop_next1_right:
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br label %loop_next1
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loop_next1:
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br i1 %c2, label %loop_next2_left, label %loop_next2_right
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loop_next2_left:
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br label %loop_next2
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loop_next2_right:
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br label %loop_next2
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loop_next2:
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br i1 %c3, label %loop_next3_left, label %loop_next3_right
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loop_next3_left:
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br label %loop_next3
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loop_next3_right:
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br label %loop_next3
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loop_next3:
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br i1 %c4, label %loop_next4_left, label %loop_next4_right
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loop_next4_left:
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br label %loop_next4
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loop_next4_right:
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br label %loop_next4
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loop_next4:
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br i1 %c5, label %loop_latch_left, label %loop_latch_right
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loop_latch_left:
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br label %loop_latch
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loop_latch_right:
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br label %loop_latch
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loop_latch:
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store volatile i32 0, i32* %addr1
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%test_loop = icmp slt i32 %iv3, 50
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br i1 %test_loop, label %loop, label %middle_latch
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middle_latch:
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store volatile i32 0, i32* %addr2
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%test_middle = icmp slt i32 %iv2, 50
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br i1 %test_middle, label %middle, label %outer_latch
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outer_latch:
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store volatile i32 0, i32* %addr3
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%test_outer = icmp slt i32 %iv1, 50
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br i1 %test_outer, label %outer, label %exit
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exit:
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ret void
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}
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