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[SPIRV] Prevent creation of jump tables from switch #82287

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Merged
merged 3 commits into from
Feb 22, 2024
Merged

[SPIRV] Prevent creation of jump tables from switch #82287

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e052583
prevent creation of jump tables from switch
VyacheslavLevytskyy Feb 19, 2024
d0ce647
prevent creation of jump tables from switch
VyacheslavLevytskyy Feb 19, 2024
f255110
change the callback; add test
VyacheslavLevytskyy Feb 20, 2024
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3 changes: 3 additions & 0 deletions llvm/lib/Target/SPIRV/SPIRVISelLowering.h
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,9 @@ class SPIRVTargetLowering : public TargetLowering {
return true;
}

// prevent creation of jump tables
bool areJTsAllowed(const Function *) const override { return false; }

// This is to prevent sexts of non-i64 vector indices which are generated
// within general IRTranslator hence type generation for it is omitted.
MVT getVectorIdxTy(const DataLayout &DL) const override {
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30 changes: 30 additions & 0 deletions llvm/test/CodeGen/SPIRV/switch-no-jump-table.ll
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@@ -0,0 +1,30 @@
; The test is to check that jump tables are not generated from switch

; RUN: llc -O0 -mtriple=spirv32-unknown-unknown %s -o - | FileCheck %s
; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s -o - -filetype=obj | spirv-val %}

; CHECK: OpSwitch %[[#]] %[[Label:]]
; CHECK-4: OpBranch %[[Label]]

target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64"
target triple = "spir64-unknown-unknown"

define spir_func void @foo(i32 noundef %val) {
entry:
switch i32 %val, label %sw.epilog [
i32 0, label %sw.bb
i32 1, label %sw.bb2
i32 2, label %sw.bb3
i32 3, label %sw.bb4
]
sw.bb:
br label %sw.epilog
sw.bb2:
br label %sw.epilog
sw.bb3:
br label %sw.epilog
sw.bb4:
br label %sw.epilog
sw.epilog:
ret void
}