[clang] Alias cc modifier to c #127719
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[clang] Alias cc modifier to c #127719
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@llvm/pr-subscribers-clang Author: None (PiJoules) ChangesFull diff: https://github.com/llvm/llvm-project/pull/127719.diff 4 Files Affected:
diff --git a/clang/lib/AST/Stmt.cpp b/clang/lib/AST/Stmt.cpp
index 685c00d0cb44f..c8ff2ecea20cc 100644
--- a/clang/lib/AST/Stmt.cpp
+++ b/clang/lib/AST/Stmt.cpp
@@ -708,6 +708,13 @@ unsigned GCCAsmStmt::AnalyzeAsmString(SmallVectorImpl<AsmStringPiece>&Pieces,
DiagOffs = CurPtr-StrStart-1;
return diag::err_asm_invalid_escape;
}
+
+ // Specifically handle `cc` which we will alias to `c`.
+ // Note this is the only operand modifier that exists which has two
+ // characters.
+ if (EscapedChar == 'c' && *CurPtr == 'c')
+ CurPtr++;
+
EscapedChar = *CurPtr++;
}
diff --git a/clang/test/AST/cc-modifier.cc b/clang/test/AST/cc-modifier.cc
new file mode 100644
index 0000000000000..24eb105acd2b7
--- /dev/null
+++ b/clang/test/AST/cc-modifier.cc
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -verify
+// expected-no-diagnostics
+
+void func();
+void func2();
+
+bool func3() {
+ __asm__("%cc0 = %c1" : : "X"(func), "X"(func2));
+ return func2 == func;
+}
diff --git a/clang/test/AST/cc-modifier.cpp b/clang/test/AST/cc-modifier.cpp
new file mode 100644
index 0000000000000..24eb105acd2b7
--- /dev/null
+++ b/clang/test/AST/cc-modifier.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu %s -verify
+// expected-no-diagnostics
+
+void func();
+void func2();
+
+bool func3() {
+ __asm__("%cc0 = %c1" : : "X"(func), "X"(func2));
+ return func2 == func;
+}
diff --git a/clang/test/CodeGen/asm.c b/clang/test/CodeGen/asm.c
index 10102cc2c4db1..9687c993e6464 100644
--- a/clang/test/CodeGen/asm.c
+++ b/clang/test/CodeGen/asm.c
@@ -284,3 +284,9 @@ void *t33(void *ptr)
// CHECK: @t33
// CHECK: %1 = call ptr asm "lea $1, $0", "=r,p,~{dirflag},~{fpsr},~{flags}"(ptr %0)
}
+
+void t34(void) {
+ __asm__ volatile("T34 CC NAMED MODIFIER: %cc[input]" :: [input] "i" (4));
+ // CHECK: @t34()
+ // CHECK: T34 CC NAMED MODIFIER: ${0:c}
+}
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Thanks for the fix! The changes should come with a release note in clang/docs/ReleaseNotes.rst
I'm not super familiar with GCC Asm Statements, but the changes look correct to me otherwise.
https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#GenericOperandmodifiers provides the `c` and `cc` modifiers. GCC 15 introduces the `cc` modifier which does the same as `c`. This patch lets Clang handle this for compatibility.
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petrhosek
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Feb 26, 2025
shafik
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It seems like for gcc at least, IIUC, cc does a bit more than c so while we are supporting cc for compatibility we are not fully supporting it? Specifically:
except try harder to print it with no punctuation
Perhaps we should document that in the comment in Stmt.cpp, for gcc comparability but not totally equivalent?
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In our testing, Clang's |
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If that is the case then I think we are good. |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/186/builds/6897 Here is the relevant piece of the build log for the reference |
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https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#GenericOperandmodifiers provides the
candccmodifiers. GCC 15 introduces theccmodifier which does the same asc. This patch lets Clang handle this for compatibility.