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[NVPTX] Fix NVPTXLowerUnreachable::isLoweredToTrap logic #109730

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Merged
merged 1 commit into from
Sep 25, 2024
Merged

[NVPTX] Fix NVPTXLowerUnreachable::isLoweredToTrap logic #109730

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21 changes: 14 additions & 7 deletions llvm/lib/Target/NVPTX/NVPTXLowerUnreachable.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -110,17 +110,24 @@ StringRef NVPTXLowerUnreachable::getPassName() const {
}

// =============================================================================
// Returns whether a `trap` intrinsic should be emitted before I.
// Returns whether a `trap` intrinsic would be emitted before I.
//
// This is a copy of the logic in SelectionDAGBuilder::visitUnreachable().
// =============================================================================
bool NVPTXLowerUnreachable::isLoweredToTrap(const UnreachableInst &I) const {
if (!TrapUnreachable)
return false;
if (!NoTrapAfterNoreturn)
return true;
const CallInst *Call = dyn_cast_or_null<CallInst>(I.getPrevNode());
return Call && Call->doesNotReturn();
if (const auto *Call = dyn_cast_or_null<CallInst>(I.getPrevNode())) {
// We've already emitted a non-continuable trap.
if (Call->isNonContinuableTrap())
return true;

// No traps are emitted for calls that do not return
// when this option is enabled.
if (NoTrapAfterNoreturn && Call->doesNotReturn())
return false;
}

// In all other cases, we will generate a trap if TrapUnreachable is set.
return TrapUnreachable;
}

// =============================================================================
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26 changes: 21 additions & 5 deletions llvm/test/CodeGen/NVPTX/unreachable.ll
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Original file line number Diff line number Diff line change
@@ -1,18 +1,23 @@
; RUN: llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs \
; RUN: llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs -trap-unreachable=false \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOTRAP
; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs \
; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -trap-unreachable=false \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOTRAP
; RUN: llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs -trap-unreachable \
; RUN: llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -no-trap-after-noreturn \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOTRAP
; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -no-trap-after-noreturn \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-NOTRAP
; RUN: llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -no-trap-after-noreturn=false \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-TRAP
; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -trap-unreachable \
; RUN: llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs -trap-unreachable -no-trap-after-noreturn=false \
; RUN: | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-TRAP
; RUN: %if ptxas && !ptxas-12.0 %{ llc < %s -march=nvptx -mcpu=sm_20 -verify-machineinstrs | %ptxas-verify %}
; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_20 -verify-machineinstrs | %ptxas-verify %}

; CHECK: .extern .func throw
declare void @throw() #0
declare void @llvm.trap() #0

; CHECK: .entry kernel_func
; CHECK-LABEL: .entry kernel_func
define void @kernel_func() {
; CHECK: call.uni
; CHECK: throw,
Expand All @@ -24,6 +29,17 @@ define void @kernel_func() {
unreachable
}

; CHECK-LABEL: kernel_func_2
define void @kernel_func_2() {
; CHECK: trap; exit;
call void @llvm.trap()

;; Make sure we avoid emitting two trap instructions.
; CHECK-NOT: trap;
; CHECK-NOT: exit;
unreachable
}

attributes #0 = { noreturn }


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