maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/test/CodeGen/WebAssembly/switch-unreachable-default.ll

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

88 lines
1.6 KiB
LLVM
Raw Normal View History

Reland "[WebAssembly] Eliminate range checks on br_tables" This reverts commit 755a89591528b692315ad0325347e2fd4637271b. Although I was not able to reproduce any test failures locally, aheejin was able to reproduce them and found a fix, applied here.
2020-06-04 05:04:59 +08:00
; RUN: llc < %s -asm-verbose=false -verify-machineinstrs | FileCheck %s
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"
; Test that switches are lowered correctly in the presence of an
; unreachable default branch target.
; CHECK-LABEL: foo:
; CHECK-NEXT: .functype foo (i32) -> (i32)
; CHECK-NEXT: block
; CHECK-NEXT: block
; CHECK-NEXT: local.get 0
; CHECK-NEXT: br_table {0, 1, 0}
; CHECK-NEXT: .LBB0_1:
; CHECK-NEXT: end_block
; CHECK-NEXT: i32.const 0
; CHECK-NEXT: return
; CHECK-NEXT: .LBB0_2:
; CHECK-NEXT: end_block
; CHECK-NEXT: i32.const 1
; CHECK-NEXT: end_function
define i32 @foo(i32 %x) {
entry:
switch i32 %x, label %unreachable [
i32 0, label %bb0
i32 1, label %bb1
]
bb0:
ret i32 0
bb1:
ret i32 1
unreachable:
unreachable
}
[WebAssembly] Fix bug in FixBrTables and use branch analysis utils Summary: This commit fixes a bug in the FixBrTables pass in which an unconditional branch from the switch header block to the jump table block was not removed before the blocks were combined. The result was an invalid CFG in the MachineFunction. This commit also switches from using bespoke branch analysis and deletion code to using the standard utilities for the same. Reviewers: aheejin, dschuff Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D81909
2020-06-18 03:34:45 +08:00
; CHECK-LABEL: split:
; CHECK: .functype split (i32) -> ()
; CHECK: block
; CHECK: br_if 0
; CHECK: block
; CHECK: block
[BPI] Improve static heuristics for "cold" paths. Current approach doesn't work well in cases when multiple paths are predicted to be "cold". By "cold" paths I mean those containing "unreachable" instruction, call marked with 'cold' attribute and 'unwind' handler of 'invoke' instruction. The issue is that heuristics are applied one by one until the first match and essentially ignores relative hotness/coldness of other paths. New approach unifies processing of "cold" paths by assigning predefined absolute weight to each block estimated to be "cold". Then we propagate these weights up/down IR similarly to existing approach. And finally set up edge probabilities based on estimated block weights. One important difference is how we propagate weight up. Existing approach propagates the same weight to all blocks that are post-dominated by a block with some "known" weight. This is useless at least because it always gives 50\50 distribution which is assumed by default anyway. Worse, it causes the algorithm to skip further heuristics and can miss setting more accurate probability. New algorithm propagates the weight up only to the blocks that dominates and post-dominated by a block with some "known" weight. In other words, those blocks that are either always executed or not executed together. In addition new approach processes loops in an uniform way as well. Essentially loop exit edges are estimated as "cold" paths relative to back edges and should be considered uniformly with other coldness/hotness markers. Reviewed By: yrouban Differential Revision: https://reviews.llvm.org/D79485
2020-06-18 17:20:55 +08:00
; CHECK: br_table {1, 1, 0}
[WebAssembly] Fix bug in FixBrTables and use branch analysis utils Summary: This commit fixes a bug in the FixBrTables pass in which an unconditional branch from the switch header block to the jump table block was not removed before the blocks were combined. The result was an invalid CFG in the MachineFunction. This commit also switches from using bespoke branch analysis and deletion code to using the standard utilities for the same. Reviewers: aheejin, dschuff Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D81909
2020-06-18 03:34:45 +08:00
; CHECK: .LBB1_2
; CHECK: end_block
[BPI] Improve static heuristics for "cold" paths. Current approach doesn't work well in cases when multiple paths are predicted to be "cold". By "cold" paths I mean those containing "unreachable" instruction, call marked with 'cold' attribute and 'unwind' handler of 'invoke' instruction. The issue is that heuristics are applied one by one until the first match and essentially ignores relative hotness/coldness of other paths. New approach unifies processing of "cold" paths by assigning predefined absolute weight to each block estimated to be "cold". Then we propagate these weights up/down IR similarly to existing approach. And finally set up edge probabilities based on estimated block weights. One important difference is how we propagate weight up. Existing approach propagates the same weight to all blocks that are post-dominated by a block with some "known" weight. This is useless at least because it always gives 50\50 distribution which is assumed by default anyway. Worse, it causes the algorithm to skip further heuristics and can miss setting more accurate probability. New algorithm propagates the weight up only to the blocks that dominates and post-dominated by a block with some "known" weight. In other words, those blocks that are either always executed or not executed together. In addition new approach processes loops in an uniform way as well. Essentially loop exit edges are estimated as "cold" paths relative to back edges and should be considered uniformly with other coldness/hotness markers. Reviewed By: yrouban Differential Revision: https://reviews.llvm.org/D79485
2020-06-18 17:20:55 +08:00
; CHECK: br_table {0, 0, 0, 0, 0, 0, 0, 0}
[WebAssembly] Fix bug in FixBrTables and use branch analysis utils Summary: This commit fixes a bug in the FixBrTables pass in which an unconditional branch from the switch header block to the jump table block was not removed before the blocks were combined. The result was an invalid CFG in the MachineFunction. This commit also switches from using bespoke branch analysis and deletion code to using the standard utilities for the same. Reviewers: aheejin, dschuff Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D81909
2020-06-18 03:34:45 +08:00
; CHECK: .LBB1_3
; CHECK: end_block
; CHECK: unreachable
; CHECK: .LBB1_4
; CHECK: end_block
; CHECK: end_function
define void @split(i8 %c) {
entry:
switch i8 %c, label %sw.default [
i8 114, label %return
i8 103, label %sw.bb1
i8 98, label %sw.bb2
i8 97, label %sw.bb3
i8 48, label %sw.bb4
i8 49, label %sw.bb5
]
sw.bb1:
unreachable
sw.bb2:
unreachable
sw.bb3:
unreachable
sw.bb4:
unreachable
sw.bb5:
unreachable
sw.default:
unreachable
return:
ret void
}