[X86] Fix TC_RETURN selection failure for Win+Thunk combination#175977
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[X86] Fix TC_RETURN selection failure for Win+Thunk combination#175977
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llvm#158055 added a IsNotWin64CCFunc predicate to these cases for reasons that are not super clear to me, which causes selection failures as this combination is not covered elsewhere.
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@llvm/pr-subscribers-backend-x86 Author: Nikita Popov (nikic) Changes#158055 added a IsNotWin64CCFunc predicate to these cases for reasons that are not super clear to me, which causes selection failures as this combination is not covered elsewhere. Fixes #175965. Disclaimer: I have no clue what I'm doing here, I just observed that this fixed the selection failure without affecting existing tests. 2 Files Affected:
diff --git a/llvm/lib/Target/X86/X86InstrCompiler.td b/llvm/lib/Target/X86/X86InstrCompiler.td
index ec31675731b79..d3acfc86ab54f 100644
--- a/llvm/lib/Target/X86/X86InstrCompiler.td
+++ b/llvm/lib/Target/X86/X86InstrCompiler.td
@@ -1381,11 +1381,11 @@ def : Pat<(X86tcret_6regs (load addr:$dst), timm:$off),
def : Pat<(X86tcret ptr_rc_tailcall:$dst, timm:$off),
(INDIRECT_THUNK_TCRETURN64 ptr_rc_tailcall:$dst, timm:$off)>,
- Requires<[In64BitMode, IsNotWin64CCFunc, UseIndirectThunkCalls]>;
+ Requires<[In64BitMode, UseIndirectThunkCalls]>;
def : Pat<(X86tcret ptr_rc_tailcall:$dst, timm:$off),
(INDIRECT_THUNK_TCRETURN32 ptr_rc_tailcall:$dst, timm:$off)>,
- Requires<[Not64BitMode, IsNotWin64CCFunc, UseIndirectThunkCalls]>;
+ Requires<[Not64BitMode, UseIndirectThunkCalls]>;
def : Pat<(X86tcret (i64 tglobaladdr:$dst), timm:$off),
(TCRETURNdi64 tglobaladdr:$dst, timm:$off)>,
diff --git a/llvm/test/CodeGen/X86/replace-thunk-tail-win.ll b/llvm/test/CodeGen/X86/replace-thunk-tail-win.ll
new file mode 100644
index 0000000000000..e1d2a3425886b
--- /dev/null
+++ b/llvm/test/CodeGen/X86/replace-thunk-tail-win.ll
@@ -0,0 +1,19 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck %s --check-prefix=64BIT
+; RUN: llc -mtriple=i686-unknown-linux-gnu < %s | FileCheck %s --check-prefix=32BIT
+
+define void @test(ptr %g) #0 {
+; 64BIT-LABEL: test:
+; 64BIT: # %bb.0:
+; 64BIT-NEXT: movq %rdi, %r11
+; 64BIT-NEXT: jmp __x86_indirect_thunk_r11 # TAILCALL
+;
+; 32BIT-LABEL: test:
+; 32BIT: # %bb.0:
+; 32BIT-NEXT: movl {{[0-9]+}}(%esp), %eax
+; 32BIT-NEXT: jmp __x86_indirect_thunk_eax # TAILCALL
+ tail call void %g()
+ ret void
+}
+
+attributes #0 = { "target-features"="+retpoline-external-thunk" }
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arsenm
approved these changes
Jan 14, 2026
dpaoliello
approved these changes
Jan 14, 2026
| ret void | ||
| } | ||
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| attributes #0 = { "target-features"="+retpoline-external-thunk" } |
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BTW, Original issue #175965 has
attribute attributes #0 = { "target-features"="+retpoline-indirect-calls" }
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Author
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The original, non-reduced case had both. I found this variant made for an easier to understand test case than +retpoline-indirect-calls.
c-rhodes
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Jan 15, 2026
…#175977) llvm#158055 added a IsNotWin64CCFunc predicate to these cases for reasons that are not super clear to me, which causes selection failures as this combination is not covered elsewhere. Fixes llvm#175965. (cherry picked from commit 2789ad2)
Priyanshu3820
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Jan 18, 2026
…#175977) llvm#158055 added a IsNotWin64CCFunc predicate to these cases for reasons that are not super clear to me, which causes selection failures as this combination is not covered elsewhere. Fixes llvm#175965.
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#158055 added a IsNotWin64CCFunc predicate to these cases for reasons that are not super clear to me, which causes selection failures as this combination is not covered elsewhere.
Fixes #175965.
Disclaimer: I have no clue what I'm doing here, I just observed that this fixed the selection failure without affecting existing tests.