[NVPTX] Fix NVPTXLowerUnreachable::isLoweredToTrap logic #109730
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@llvm/pr-subscribers-backend-nvptx Author: duk (duk-37) ChangesPreviously, this pass would not generate traps if Fix both of these problems and add some tests. Full diff: https://github.com/llvm/llvm-project/pull/109730.diff 2 Files Affected:
diff --git a/llvm/lib/Target/NVPTX/NVPTXLowerUnreachable.cpp b/llvm/lib/Target/NVPTX/NVPTXLowerUnreachable.cpp
index 92b90e2559154e..ef0d0e7cd7d510 100644
--- a/llvm/lib/Target/NVPTX/NVPTXLowerUnreachable.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXLowerUnreachable.cpp
@@ -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 (Call) {
+ // 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;
}
// =============================================================================
diff --git a/llvm/test/CodeGen/NVPTX/unreachable.ll b/llvm/test/CodeGen/NVPTX/unreachable.ll
index 011497c4e23401..f9118900cb7372 100644
--- a/llvm/test/CodeGen/NVPTX/unreachable.ll
+++ b/llvm/test/CodeGen/NVPTX/unreachable.ll
@@ -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,
@@ -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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✅ With the latest revision this PR passed the C/C++ code formatter. |
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FYI I don't have commit access anymore so you'll have to merge it in. :) |
Previously, this pass would not generate traps if `NoTrapAfterNoreturn` was set and would generate traps even if the instruction directly before the `UnreachableInst` was `llvm.trap()`.
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/30/builds/6951 Here is the relevant piece of the build log for the reference |
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Previously, this pass would not generate traps if
NoTrapAfterNoreturnwas set and would generate traps even if the instruction directly before theUnreachableInstwasllvm.trap().Fix both of these problems and add some tests.