[llvm] 1b1270f - [FMV][GlobalOpt] Enable static resolution of non-FMV callers. (#124314)

[via llvm-commits]

Author: Alexandros Lamprineas
Date: 2025-01-24T19:48:40Z
New Revision: 1b1270f30bbdb2c7a310009d0512e167b09bac48

URL: https://github.com/llvm/llvm-project/commit/1b1270f30bbdb2c7a310009d0512e167b09bac48
DIFF: https://github.com/llvm/llvm-project/commit/1b1270f30bbdb2c7a310009d0512e167b09bac48.diff

LOG: [FMV][GlobalOpt] Enable static resolution of non-FMV callers. (#124314)

The undetectable FMV features predres and ls64 have been removed,
therefore the optimization is now re-enabled. The llvm testsuite
Graviton4 bots are expected to remain green.

Added: 
    

Modified: 
    llvm/lib/Transforms/IPO/GlobalOpt.cpp
    llvm/test/Transforms/GlobalOpt/resolve-fmv-ifunc.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 00c20ad5f37094..9586fc97a39f70 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -95,20 +95,11 @@ STATISTIC(NumIFuncsDeleted, "Number of IFuncs removed");
 STATISTIC(NumGlobalArraysPadded,
           "Number of global arrays padded to alignment boundary");
 
-// FIXME:
-// Optimizing non-FMV callers is causing a regression in the llvm test suite,
-// specifically a 'predres' version is unexpectedly trapping on GravitonG4.
-// My explanation is that when the caller in not a versioned function, the
-// compiler exclusively relies on the command line option, or target attribute
-// to deduce whether a feature is available. However, there is no guarantee
-// that in reality the host supports those implied features, which arguably
-// is a user error. This option allows disabling the optimization as a short
-// term workaround to keep the bots green.
 static cl::opt<bool>
     OptimizeNonFMVCallers("optimize-non-fmv-callers",
                           cl::desc("Statically resolve calls to versioned "
                                    "functions from non-versioned callers."),
-                          cl::init(false), cl::Hidden);
+                          cl::init(true), cl::Hidden);
 
 static cl::opt<bool>
     EnableColdCCStressTest("enable-coldcc-stress-test",

diff  --git a/llvm/test/Transforms/GlobalOpt/resolve-fmv-ifunc.ll b/llvm/test/Transforms/GlobalOpt/resolve-fmv-ifunc.ll
index fa817a8cbf417f..4b6a19d3f05cf5 100644
--- a/llvm/test/Transforms/GlobalOpt/resolve-fmv-ifunc.ll
+++ b/llvm/test/Transforms/GlobalOpt/resolve-fmv-ifunc.ll
@@ -221,7 +221,7 @@ resolver_entry:
 define i32 @caller4() #8 {
 ; CHECK-LABEL: define i32 @caller4(
 ; CHECK-SAME: ) local_unnamed_addr #[[ATTR7:[0-9]+]] {
-; CHECK:    [[CALL:%.*]] = tail call i32 @test_non_fmv_caller()
+; CHECK:    [[CALL:%.*]] = tail call i32 @test_non_fmv_caller._Maes()
 ;
 entry:
   %call = tail call i32 @test_non_fmv_caller()