[llvm] [IROutliner] Prevent propagating interrupt attribute (PR #153985)
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Sat Aug 16 16:37:19 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-risc-v
Author: Sam Elliott (lenary)
<details>
<summary>Changes</summary>
On RISC-V, the interrupt attribute relates only to the prolog and epilog of the attributed function (and has specific restrictions on the function's signature). It does not change how that function calls other functions, and when outlining, the outlined function must not have this attribute.
Fixes #<!-- -->149969
---
Full diff: https://github.com/llvm/llvm-project/pull/153985.diff
2 Files Affected:
- (modified) llvm/lib/Transforms/IPO/IROutliner.cpp (+7-1)
- (added) llvm/test/Transforms/IROutliner/outlining-compatible-and-never-transfer-riscv.ll (+298)
``````````diff
diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
index c57981ae4ca0d..045945b25eeb8 100644
--- a/llvm/lib/Transforms/IPO/IROutliner.cpp
+++ b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -2235,8 +2235,14 @@ static void fillOverallFunction(
*CurrentGroup.OutlinedFunction, CurrentGroup.EndBBs);
// Transfer the attributes from the function to the new function.
- for (Attribute A : CurrentOS->ExtractedFunction->getAttributes().getFnAttrs())
+ for (Attribute A : CurrentOS->ExtractedFunction->getAttributes().getFnAttrs()) {
+ // QC-Specific - Begin
+ if (M.getTargetTriple().isRISCV() && A.getKindAsString() == "interrupt")
+ continue;
+ // QC-Specific - End
+
CurrentGroup.OutlinedFunction->addFnAttr(A);
+ }
// Create a new set of output blocks for the first extracted function.
DenseMap<Value *, BasicBlock *> NewBBs;
diff --git a/llvm/test/Transforms/IROutliner/outlining-compatible-and-never-transfer-riscv.ll b/llvm/test/Transforms/IROutliner/outlining-compatible-and-never-transfer-riscv.ll
new file mode 100644
index 0000000000000..937ee963f6087
--- /dev/null
+++ b/llvm/test/Transforms/IROutliner/outlining-compatible-and-never-transfer-riscv.ll
@@ -0,0 +1,298 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --function-signature --check-globals --include-generated-funcs
+; RUN: opt -mtriple=riscv32 -S -passes=verify,iroutliner -ir-outlining-no-cost < %s | FileCheck %s
+
+; REQUIRES: riscv-registered-target
+
+; This has two compatible regions based on function attributes. We have attributes
+; that should never be transferred to the outlined functions:
+; - `interrupt`=*
+
+; On RISC-V, the `interrupt` attribute only applies to the prolog and epilog of
+; the annotated function, and not any functions it calls. If this attribute is
+; preserved, there will be codegen errors because of restrictions on the
+; signatures of `interrupt` attributes.
+
+define void @outline_attrs1() #0 {
+entry:
+ %a = alloca i32, align 4
+ %b = alloca i32, align 4
+ %c = alloca i32, align 4
+ store i32 2, ptr %a, align 4
+ store i32 3, ptr %b, align 4
+ store i32 4, ptr %c, align 4
+ %al = load i32, ptr %a
+ %bl = load i32, ptr %b
+ %cl = load i32, ptr %c
+ ret void
+}
+
+define void @outline_attrs2() #1 {
+entry:
+ %a = alloca i32, align 4
+ %b = alloca i32, align 4
+ %c = alloca i32, align 4
+ store i32 2, ptr %a, align 4
+ store i32 3, ptr %b, align 4
+ store i32 4, ptr %c, align 4
+ %al = load i32, ptr %a
+ %bl = load i32, ptr %b
+ %cl = load i32, ptr %c
+ ret void
+}
+
+define void @outline_attrs3() {
+entry:
+ %a = alloca i32, align 4
+ %b = alloca i32, align 4
+ %c = alloca i32, align 4
+ store i32 2, ptr %a, align 4
+ store i32 3, ptr %b, align 4
+ store i32 4, ptr %c, align 4
+ %al = load i32, ptr %a
+ %bl = load i32, ptr %b
+ %cl = load i32, ptr %c
+ ret void
+}
+
+define void @outline_outputs1() #0 {
+entry:
+ %output = alloca i32, align 4
+ %result = alloca i32, align 4
+ %output2 = alloca i32, align 4
+ %result2 = alloca i32, align 4
+ %a = alloca i32, align 4
+ %b = alloca i32, align 4
+ br label %block_2
+block_1:
+ %a2 = alloca i32, align 4
+ %b2 = alloca i32, align 4
+ br label %block_2
+block_2:
+ %a2val = load i32, ptr %a
+ %b2val = load i32, ptr %b
+ %add2 = add i32 2, %a2val
+ %mul2 = mul i32 2, %b2val
+ br label %block_5
+block_3:
+ %aval = load i32, ptr %a
+ %bval = load i32, ptr %b
+ %add = add i32 2, %aval
+ %mul = mul i32 2, %bval
+ br label %block_4
+block_4:
+ store i32 %add, ptr %output, align 4
+ store i32 %mul, ptr %result, align 4
+ br label %block_6
+block_5:
+ store i32 %add2, ptr %output, align 4
+ store i32 %mul2, ptr %result, align 4
+ br label %block_7
+block_6:
+ ret void
+block_7:
+ ret void
+}
+
+define void @outline_outputs2() #1 {
+entry:
+ %output = alloca i32, align 4
+ %result = alloca i32, align 4
+ %output2 = alloca i32, align 4
+ %result2 = alloca i32, align 4
+ %a = alloca i32, align 4
+ %b = alloca i32, align 4
+ br label %block_2
+block_1:
+ %a2 = alloca i32, align 4
+ %b2 = alloca i32, align 4
+ br label %block_2
+block_2:
+ %a2val = load i32, ptr %a
+ %b2val = load i32, ptr %b
+ %add2 = add i32 2, %a2val
+ %mul2 = mul i32 2, %b2val
+ br label %block_5
+block_3:
+ %aval = load i32, ptr %a
+ %bval = load i32, ptr %b
+ %add = add i32 2, %aval
+ %mul = mul i32 2, %bval
+ br label %block_4
+block_4:
+ store i32 %add, ptr %output, align 4
+ store i32 %mul, ptr %result, align 4
+ br label %block_7
+block_5:
+ store i32 %add2, ptr %output, align 4
+ store i32 %mul2, ptr %result, align 4
+ br label %block_6
+block_6:
+ %diff = sub i32 %a2val, %b2val
+ ret void
+block_7:
+ %quot = udiv i32 %add, %mul
+ ret void
+}
+
+attributes #0 = { "interrupt"="machine" }
+attributes #1 = { "interrupt"="qci-nest" }
+; CHECK-LABEL: define {{[^@]+}}@outline_attrs1
+; CHECK-SAME: () #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[A:%.*]] = all oca i32, align 4
+; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT: call void @outlined_ir_func_1(ptr [[A]], ptr [[B]], ptr [[C]])
+; CHECK-NEXT: ret void
+;
+;
+; CHECK-LABEL: define {{[^@]+}}@outline_attrs2
+; CHECK-SAME: () #[[ATTR1:[0-9]+]] {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT: call void @outlined_ir_func_1(ptr [[A]], ptr [[B]], ptr [[C]])
+; CHECK-NEXT: ret void
+;
+;
+; CHECK-LABEL: define {{[^@]+}}@outline_attrs3() {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT: call void @outlined_ir_func_1(ptr [[A]], ptr [[B]], ptr [[C]])
+; CHECK-NEXT: ret void
+;
+;
+; CHECK-LABEL: define {{[^@]+}}@outline_outputs1
+; CHECK-SAME: () #[[ATTR0]] {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[OUTPUT:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[RESULT:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[OUTPUT2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[RESULT2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT: br label [[BLOCK_2:%.*]]
+; CHECK: block_1:
+; CHECK-NEXT: [[A2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: br label [[BLOCK_2]]
+; CHECK: block_2:
+; CHECK-NEXT: [[TMP0:%.*]] = call i1 @outlined_ir_func_0(ptr [[A]], ptr [[B]], ptr [[OUTPUT]], ptr [[RESULT]], ptr null, ptr null, ptr null, ptr null, i32 -1)
+; CHECK-NEXT: br i1 [[TMP0]], label [[BLOCK_6:%.*]], label [[BLOCK_7:%.*]]
+; CHECK: block_6:
+; CHECK-NEXT: ret void
+; CHECK: block_7:
+; CHECK-NEXT: ret void
+;
+;
+; CHECK-LABEL: define {{[^@]+}}@outline_outputs2
+; CHECK-SAME: () #[[ATTR1]] {
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[MUL_LOC:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[ADD_LOC:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B2VAL_LOC:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[A2VAL_LOC:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[OUTPUT:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[RESULT:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[OUTPUT2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[RESULT2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT: br label [[BLOCK_2:%.*]]
+; CHECK: block_1:
+; CHECK-NEXT: [[A2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: [[B2:%.*]] = alloca i32, align 4
+; CHECK-NEXT: br label [[BLOCK_2]]
+; CHECK: block_2:
+; CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 -1, ptr [[A2VAL_LOC]])
+; CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 -1, ptr [[B2VAL_LOC]])
+; CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 -1, ptr [[ADD_LOC]])
+; CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 -1, ptr [[MUL_LOC]])
+; CHECK-NEXT: [[TMP0:%.*]] = call i1 @outlined_ir_func_0(ptr [[A]], ptr [[B]], ptr [[OUTPUT]], ptr [[RESULT]], ptr [[A2VAL_LOC]], ptr [[B2VAL_LOC]], ptr [[ADD_LOC]], ptr [[MUL_LOC]], i32 0)
+; CHECK-NEXT: [[A2VAL_RELOAD:%.*]] = load i32, ptr [[A2VAL_LOC]], align 4
+; CHECK-NEXT: [[B2VAL_RELOAD:%.*]] = load i32, ptr [[B2VAL_LOC]], align 4
+; CHECK-NEXT: [[ADD_RELOAD:%.*]] = load i32, ptr [[ADD_LOC]], align 4
+; CHECK-NEXT: [[MUL_RELOAD:%.*]] = load i32, ptr [[MUL_LOC]], align 4
+; CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 -1, ptr [[A2VAL_LOC]])
+; CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 -1, ptr [[B2VAL_LOC]])
+; CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 -1, ptr [[ADD_LOC]])
+; CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 -1, ptr [[MUL_LOC]])
+; CHECK-NEXT: br i1 [[TMP0]], label [[BLOCK_7:%.*]], label [[BLOCK_6:%.*]]
+; CHECK: block_6:
+; CHECK-NEXT: [[DIFF:%.*]] = sub i32 [[A2VAL_RELOAD]], [[B2VAL_RELOAD]]
+; CHECK-NEXT: ret void
+; CHECK: block_7:
+; CHECK-NEXT: [[QUOT:%.*]] = udiv i32 [[ADD_RELOAD]], [[MUL_RELOAD]]
+; CHECK-NEXT: ret void
+;
+;
+; CHECK-LABEL: define {{[^@]+}}@outlined_ir_func_0
+; CHECK-SAME: (ptr [[TMP0:%.*]], ptr [[TMP1:%.*]], ptr [[TMP2:%.*]], ptr [[TMP3:%.*]], ptr [[TMP4:%.*]], ptr [[TMP5:%.*]], ptr [[TMP6:%.*]], ptr [[TMP7:%.*]], i32 [[TMP8:%.*]]) #[[ATTR3:[0-9]+]] {
+; CHECK-NEXT: newFuncRoot:
+; CHECK-NEXT: br label [[BLOCK_2_TO_OUTLINE:%.*]]
+; CHECK: block_2_to_outline:
+; CHECK-NEXT: [[A2VAL:%.*]] = load i32, ptr [[TMP0]], align 4
+; CHECK-NEXT: [[B2VAL:%.*]] = load i32, ptr [[TMP1]], align 4
+; CHECK-NEXT: [[ADD2:%.*]] = add i32 2, [[A2VAL]]
+; CHECK-NEXT: [[MUL2:%.*]] = mul i32 2, [[B2VAL]]
+; CHECK-NEXT: br label [[BLOCK_5:%.*]]
+; CHECK: block_3:
+; CHECK-NEXT: [[AVAL:%.*]] = load i32, ptr [[TMP0]], align 4
+; CHECK-NEXT: [[BVAL:%.*]] = load i32, ptr [[TMP1]], align 4
+; CHECK-NEXT: [[ADD:%.*]] = add i32 2, [[AVAL]]
+; CHECK-NEXT: [[MUL:%.*]] = mul i32 2, [[BVAL]]
+; CHECK-NEXT: br label [[BLOCK_4:%.*]]
+; CHECK: block_4:
+; CHECK-NEXT: store i32 [[ADD]], ptr [[TMP2]], align 4
+; CHECK-NEXT: store i32 [[MUL]], ptr [[TMP3]], align 4
+; CHECK-NEXT: br label [[BLOCK_6_EXITSTUB:%.*]]
+; CHECK: block_5:
+; CHECK-NEXT: store i32 [[ADD2]], ptr [[TMP2]], align 4
+; CHECK-NEXT: store i32 [[MUL2]], ptr [[TMP3]], align 4
+; CHECK-NEXT: br label [[BLOCK_7_EXITSTUB:%.*]]
+; CHECK: block_6.exitStub:
+; CHECK-NEXT: switch i32 [[TMP8]], label [[FINAL_BLOCK_1:%.*]] [
+; CHECK-NEXT: i32 0, label [[OUTPUT_BLOCK_1_1:%.*]]
+; CHECK-NEXT: ]
+; CHECK: block_7.exitStub:
+; CHECK-NEXT: switch i32 [[TMP8]], label [[FINAL_BLOCK_0:%.*]] [
+; CHECK-NEXT: i32 0, label [[OUTPUT_BLOCK_1_0:%.*]]
+; CHECK-NEXT: ]
+; CHECK: output_block_1_0:
+; CHECK-NEXT: store i32 [[A2VAL]], ptr [[TMP4]], align 4
+; CHECK-NEXT: store i32 [[B2VAL]], ptr [[TMP5]], align 4
+; CHECK-NEXT: br label [[FINAL_BLOCK_0]]
+; CHECK: output_block_1_1:
+; CHECK-NEXT: store i32 [[ADD]], ptr [[TMP6]], align 4
+; CHECK-NEXT: store i32 [[MUL]], ptr [[TMP7]], align 4
+; CHECK-NEXT: br label [[FINAL_BLOCK_1]]
+; CHECK: final_block_0:
+; CHECK-NEXT: ret i1 false
+; CHECK: final_block_1:
+; CHECK-NEXT: ret i1 true
+;
+;
+; CHECK-LABEL: define {{[^@]+}}@outlined_ir_func_1
+; CHECK-SAME: (ptr [[TMP0:%.*]], ptr [[TMP1:%.*]], ptr [[TMP2:%.*]]) #[[ATTR3]] {
+; CHECK-NEXT: newFuncRoot:
+; CHECK-NEXT: br label [[ENTRY_TO_OUTLINE:%.*]]
+; CHECK: entry_to_outline:
+; CHECK-NEXT: store i32 2, ptr [[TMP0]], align 4
+; CHECK-NEXT: store i32 3, ptr [[TMP1]], align 4
+; CHECK-NEXT: store i32 4, ptr [[TMP2]], align 4
+; CHECK-NEXT: [[AL:%.*]] = load i32, ptr [[TMP0]], align 4
+; CHECK-NEXT: [[BL:%.*]] = load i32, ptr [[TMP1]], align 4
+; CHECK-NEXT: [[CL:%.*]] = load i32, ptr [[TMP2]], align 4
+; CHECK-NEXT: br label [[ENTRY_AFTER_OUTLINE_EXITSTUB:%.*]]
+; CHECK: entry_after_outline.exitStub:
+; CHECK-NEXT: ret void
+;
+;.
+; CHECK: attributes #[[ATTR0]] = { "interrupt"="machine" }
+; CHECK: attributes #[[ATTR1]] = { "interrupt"="qci-nest" }
+; CHECK: attributes #[[ATTR2:[0-9]+]] = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+; CHECK: attributes #[[ATTR3]] = { minsize optsize }
+;.
``````````
</details>
https://github.com/llvm/llvm-project/pull/153985
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