release/21.x: [SPARC] Prevent meta instructions from being inserted into delay slots (#161111) #161937
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@arsenm What do you think about merging this PR to the release branch? |
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@llvm/pr-subscribers-backend-sparc Author: None (llvmbot) ChangesBackport 2e1fab9 Requested by: @brad0 Full diff: https://github.com/llvm/llvm-project/pull/161937.diff 2 Files Affected:
diff --git a/llvm/lib/Target/Sparc/DelaySlotFiller.cpp b/llvm/lib/Target/Sparc/DelaySlotFiller.cpp
index 6c19049a001cf..024030d196ee3 100644
--- a/llvm/lib/Target/Sparc/DelaySlotFiller.cpp
+++ b/llvm/lib/Target/Sparc/DelaySlotFiller.cpp
@@ -206,8 +206,8 @@ Filler::findDelayInstr(MachineBasicBlock &MBB,
if (!done)
--I;
- // skip debug instruction
- if (I->isDebugInstr())
+ // Skip meta instructions.
+ if (I->isMetaInstruction())
continue;
if (I->hasUnmodeledSideEffects() || I->isInlineAsm() || I->isPosition() ||
diff --git a/llvm/test/CodeGen/SPARC/2011-01-19-DelaySlot.ll b/llvm/test/CodeGen/SPARC/2011-01-19-DelaySlot.ll
index 9ccd4f1c0ac9a..767ef7eb510e6 100644
--- a/llvm/test/CodeGen/SPARC/2011-01-19-DelaySlot.ll
+++ b/llvm/test/CodeGen/SPARC/2011-01-19-DelaySlot.ll
@@ -184,4 +184,29 @@ entry:
ret i32 %2
}
+define i32 @test_generic_inst(i32 %arg) #0 {
+;CHECK-LABEL: test_generic_inst:
+;CHECK: ! fake_use: {{.*}}
+;CHECK: bne {{.*}}
+;CHECK-NEXT: nop
+ %bar1 = call i32 @bar(i32 %arg)
+ %even = and i32 %bar1, 1
+ %cmp = icmp eq i32 %even, 0
+ ; This shouldn't get reordered into a delay slot
+ call void (...) @llvm.fake.use(i32 %arg)
+ br i1 %cmp, label %true, label %false
+true:
+ %bar2 = call i32 @bar(i32 %bar1)
+ br label %cont
+
+false:
+ %inc = add nsw i32 %bar1, 1
+ br label %cont
+
+cont:
+ %ret = phi i32 [ %bar2, %true ], [ %inc, %false ]
+ ret i32 %ret
+}
+
+declare void @llvm.fake.use(...)
attributes #0 = { nounwind "disable-tail-calls"="true" }
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arsenm
approved these changes
Oct 4, 2025
github-project-automation
bot
moved this from Needs Review
to Needs Merge
in LLVM Release Status
llvm#161111) Do not move meta instructions like `FAKE_USE`/`@llvm.fake.use` into delay slots, as they don't correspond to real machine instructions. This should fix crashes when compiling with, for example, `clang -Og`. (cherry picked from commit 2e1fab9)
github-project-automation
bot
moved this from Needs Merge
to Done
in LLVM Release Status
|
@brad0 (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR. |
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Backport 2e1fab9
Requested by: @brad0