1469d82e1c
As defined in LangRef, branching on `undef` is undefined behavior. This PR aims to remove undefined behavior from tests. As UB tests break Alive2 and may be the root cause of breaking future optimizations. Here's an Alive2 proof for one of the examples: https://alive2.llvm.org/ce/z/TncxhP
154 lines
4.5 KiB
LLVM
154 lines
4.5 KiB
LLVM
; RUN: opt < %s -passes='print<branch-prob>' -disable-output 2>&1 | FileCheck %s
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declare void @bar() cold
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; Both 'l1' and 'r1' has one edge leading to 'cold' and another one to
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; 'unreachable' blocks. Check that 'cold' paths are preferred. Also ensure both
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; paths from 'entry' block are equal.
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define void @test1(i32 %0, i1 %arg) {
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;CHECK: edge %entry -> %l1 probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %entry -> %r1 probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %l1 -> %cold probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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;CHECK: edge %l1 -> %unreached probability is 0x00000000 / 0x80000000 = 0.00%
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;CHECK: edge %r1 -> %unreached probability is 0x00000000 / 0x80000000 = 0.00%
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;CHECK: edge %r1 -> %cold probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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entry:
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br i1 %arg, label %l1, label %r1
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l1:
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br i1 %arg, label %cold, label %unreached
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r1:
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br i1 %arg, label %unreached, label %cold
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unreached:
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unreachable
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cold:
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call void @bar()
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ret void
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}
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; Both edges of 'l1' leads to 'cold' blocks while one edge of 'r1' leads to
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; 'unreachable' block. Check that 'l1' has 50/50 while 'r1' has 0/100
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; distributuion. Also ensure both paths from 'entry' block are equal.
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define void @test2(i32 %0, i1 %arg) {
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;CHECK: edge %entry -> %l1 probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %entry -> %r1 probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %l1 -> %cold probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %l1 -> %cold2 probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %r1 -> %unreached probability is 0x00000000 / 0x80000000 = 0.00%
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;CHECK: edge %r1 -> %cold probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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entry:
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br i1 %arg, label %l1, label %r1
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l1:
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br i1 %arg, label %cold, label %cold2
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r1:
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br i1 %arg, label %unreached, label %cold
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unreached:
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unreachable
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cold:
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call void @bar()
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ret void
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cold2:
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call void @bar()
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ret void
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}
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; Both edges of 'r1' leads to 'unreachable' blocks while one edge of 'l1' leads to
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; 'cold' block. Ensure that path leading to 'cold' block is preferred.
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define void @test3(i32 %0, i1 %arg) {
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;CHECK: edge %entry -> %l1 probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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;CHECK: edge %entry -> %r1 probability is 0x00000000 / 0x80000000 = 0.00%
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;CHECK: edge %l1 -> %cold probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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;CHECK: edge %l1 -> %unreached probability is 0x00000000 / 0x80000000 = 0.00%
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;CHECK: edge %r1 -> %unreached probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %r1 -> %unreached2 probability is 0x40000000 / 0x80000000 = 50.00%
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entry:
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br i1 %arg, label %l1, label %r1
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l1:
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br i1 %arg, label %cold, label %unreached
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r1:
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br i1 %arg, label %unreached, label %unreached2
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unreached:
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unreachable
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unreached2:
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unreachable
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cold:
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call void @bar()
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ret void
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}
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; Left edge of 'entry' leads to 'cold' block while right edge is 'normal' continuation.
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; Check that we able to propagate 'cold' weight to 'entry' block. Also ensure
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; both edges from 'l1' are equally likely.
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define void @test4(i32 %0, i1 %arg) {
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;CHECK: edge %entry -> %l1 probability is 0x078780e3 / 0x80000000 = 5.88%
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;CHECK: edge %entry -> %r1 probability is 0x78787f1d / 0x80000000 = 94.12% [HOT edge]
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;CHECK: edge %l1 -> %l2 probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %l1 -> %r2 probability is 0x40000000 / 0x80000000 = 50.00%
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;CHECK: edge %l2 -> %to.cold probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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;CHECK: edge %r2 -> %to.cold probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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;CHECK: edge %to.cold -> %cold probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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entry:
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br i1 %arg, label %l1, label %r1
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l1:
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br i1 %arg, label %l2, label %r2
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l2:
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br label %to.cold
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r2:
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br label %to.cold
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to.cold:
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br label %cold
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r1:
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ret void
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cold:
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call void @bar()
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ret void
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}
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; Check that most likely path from 'entry' to 'l2' through 'r1' is preferred.
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define void @test5(i32 %0, i1 %arg) {
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;CHECK: edge %entry -> %cold probability is 0x078780e3 / 0x80000000 = 5.88%
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;CHECK: edge %entry -> %r1 probability is 0x78787f1d / 0x80000000 = 94.12% [HOT edge]
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;CHECK: edge %cold -> %l2 probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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;CHECK: edge %r1 -> %l2 probability is 0x80000000 / 0x80000000 = 100.00% [HOT edge]
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;CHECK: edge %r1 -> %unreached probability is 0x00000000 / 0x80000000 = 0.00%
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entry:
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br i1 %arg, label %cold, label %r1
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cold:
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call void @bar()
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br label %l2
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r1:
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br i1 %arg, label %l2, label %unreached
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l2:
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ret void
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unreached:
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unreachable
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}
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