[PATCH] D150396: [InlineCost] Check for conflicting target attributes early

[Kazu Hirata via Phabricator via llvm-commits]

kazu created this revision.
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When we inline a callee into a caller, the compiler needs to make sure
that the caller supports a superset of instruction sets that the
callee is allowed to use.  Normally, we check for the compatibility of
target features via functionsHaveCompatibleAttributes, but that
happens after we decide to honor call site attribute
Attribute::AlwaysInline.  If the caller contains a call marked with
Attribute::AlwaysInline, which can happen with
__attribute__((flatten)) placed on the caller, the caller could end up
with code that cannot be lowered to assembly code.

This patch fixes the problem by checking the target feature
compatibility before we honor Attribute::AlwaysInline.

Fixes https://github.com/llvm/llvm-project/issues/62664


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D150396

Files:
  llvm/lib/Analysis/InlineCost.cpp
  llvm/test/Transforms/Inline/target-features-vs-alwaysinline.ll


Index: llvm/test/Transforms/Inline/target-features-vs-alwaysinline.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/Inline/target-features-vs-alwaysinline.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt < %s -passes=inline -S | FileCheck %s
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Make sure that we do not inline callee into caller.  If we inline
+; callee into caller, caller would end pu with AVX512 intrinsics even
+; though it is not allowed to use AVX512 instructions.
+define void @caller(ptr %0) {
+; CHECK-LABEL: define void @caller
+; CHECK-SAME: (ptr [[TMP0:%.*]]) {
+; CHECK-NEXT:    call void @callee(ptr [[TMP0]], i64 0, i32 0) #[[ATTR2:[0-9]+]]
+; CHECK-NEXT:    ret void
+;
+  call void @callee(ptr %0, i64 0, i32 0) #1
+  ret void
+}
+
+define available_externally void @callee(ptr %0, i64 %1, i32 %2) #0 {
+; CHECK-LABEL: define available_externally void @callee
+; CHECK-SAME: (ptr [[TMP0:%.*]], i64 [[TMP1:%.*]], i32 [[TMP2:%.*]]) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:    [[TMP4:%.*]] = call <16 x float> @llvm.x86.avx512.min.ps.512(<16 x float> zeroinitializer, <16 x float> zeroinitializer, i32 0)
+; CHECK-NEXT:    store <16 x float> [[TMP4]], ptr [[TMP0]], align 1
+; CHECK-NEXT:    ret void
+;
+  %4 = call <16 x float> @llvm.x86.avx512.min.ps.512(<16 x float> zeroinitializer, <16 x float> zeroinitializer, i32 0)
+  store <16 x float> %4, ptr %0, align 1
+  ret void
+}
+
+declare <16 x float> @llvm.x86.avx512.min.ps.512(<16 x float>, <16 x float>, i32 immarg)
+
+attributes #0 = { "target-features"="+aes,+avx,+avx2,+avx512bw,+avx512dq,+avx512f,+avx512vl,+bmi,+bmi2,+crc32,+cx16,+cx8,+f16c,+fma,+fsgsbase,+fxsr,+invpcid,+lzcnt,+mmx,+movbe,+pclmul,+popcnt,+rdrnd,+sahf,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+ssse3,+x87,+xsave,+xsaveopt" }
+attributes #1 = { alwaysinline }
Index: llvm/lib/Analysis/InlineCost.cpp
===================================================================
--- llvm/lib/Analysis/InlineCost.cpp
+++ llvm/lib/Analysis/InlineCost.cpp
@@ -2787,16 +2787,14 @@
 /// Test that there are no attribute conflicts between Caller and Callee
 ///        that prevent inlining.
 static bool functionsHaveCompatibleAttributes(
-    Function *Caller, Function *Callee, TargetTransformInfo &TTI,
+    Function *Caller, Function *Callee,
     function_ref<const TargetLibraryInfo &(Function &)> &GetTLI) {
   // Note that CalleeTLI must be a copy not a reference. The legacy pass manager
   // caches the most recently created TLI in the TargetLibraryInfoWrapperPass
   // object, and always returns the same object (which is overwritten on each
   // GetTLI call). Therefore we copy the first result.
   auto CalleeTLI = GetTLI(*Callee);
-  return (IgnoreTTIInlineCompatible ||
-          TTI.areInlineCompatible(Caller, Callee)) &&
-         GetTLI(*Caller).areInlineCompatible(CalleeTLI,
+  return GetTLI(*Caller).areInlineCompatible(CalleeTLI,
                                              InlineCallerSupersetNoBuiltin) &&
          AttributeFuncs::areInlineCompatible(*Caller, *Callee);
 }
@@ -2912,6 +2910,14 @@
                                      " address space");
     }
 
+  // Never inline functions with conflicting target attributes.
+  Function *Caller = Call.getCaller();
+  if (!IgnoreTTIInlineCompatible &&
+      !CalleeTTI.areInlineCompatible(Caller, Callee)) {
+    fprintf(stderr, "InlineCost.cpp:%d\n", __LINE__);
+    return InlineResult::failure("conflicting target attributes");
+  }
+
   // Calls to functions with always-inline attributes should be inlined
   // whenever possible.
   if (Call.hasFnAttr(Attribute::AlwaysInline)) {
@@ -2926,8 +2932,7 @@
 
   // Never inline functions with conflicting attributes (unless callee has
   // always-inline attribute).
-  Function *Caller = Call.getCaller();
-  if (!functionsHaveCompatibleAttributes(Caller, Callee, CalleeTTI, GetTLI))
+  if (!functionsHaveCompatibleAttributes(Caller, Callee, GetTLI))
     return InlineResult::failure("conflicting attributes");
 
   // Don't inline this call if the caller has the optnone attribute.


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