LLVM21 bug workaround: getFixedValue()

src/CodeGen_LLVM.cpp

@@ -1381,7 +1381,28 @@
     // 21.04 -> 14.78 using current ToT release build. (See also https://reviews.llvm.org/rL358304)
     pto.ForgetAllSCEVInLoopUnroll = true;
 
-    llvm::PassBuilder pb(tm.get(), pto);
+    llvm::PassInstrumentationCallbacks pic;
+#if LLVM_VERSION < 220
+    if (get_target().has_feature(Target::SVE) || get_target().has_feature(Target::SVE2)) {
+        // LLVM 21's LoopAccessAnalysis::getStrideFromAddRec() queries a
+        // scalable-vector access type's fixed element count, which hits a
+        // fatal assertion (TypeSize::getFixedValue on a scalable TypeSize).
+        // This is reached from LoopLoadEliminationPass, which the default
+        // pipeline always runs (independent of Halide's own loop-opt
+        // settings). Fixed upstream in LLVM 22 by guarding that query
+        // against ScalableVectorType. Loop load elimination looks for
+        // opportunities to forward a store to a later load across loop
+        // iterations, which Halide-generated code essentially never
+        // benefits from, so skip it entirely on affected SVE targets rather
+        // than accept a compiler crash (or, in a no-asserts LLVM build, a
+        // silently bogus stride).
+        pic.registerShouldRunOptionalPassCallback(
+            [](llvm::StringRef pass_name, llvm::Any) {
+                return pass_name != "LoopLoadEliminationPass";
+            });
+    }
+#endif
+    llvm::PassBuilder pb(tm.get(), pto, /*PGOOpt=*/std::nullopt, &pic);
 
     // These analysis managers have to be declared in this order.
     llvm::LoopAnalysisManager lam;

test/autoschedulers/mullapudi2016/max_filter.cpp

@@ -128,15 +128,6 @@ int main(int argc, char **argv) {
         return 0;
     }
 
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     if (argc != 2) {
         fprintf(stderr, "Usage: %s <autoscheduler-lib>\n", argv[0]);
         return 1;

test/correctness/align_bounds.cpp

@@ -23,15 +23,6 @@ int my_trace(JITUserContext *user_context, const halide_trace_event_t *e) {
 }
 
 int main(int argc, char **argv) {
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     // Force the bounds of an intermediate pipeline stage to be even to remove a select
     {
         Func f, g, h;

test/correctness/bound_small_allocations.cpp

@@ -10,15 +10,6 @@ Expr calc(Expr a) {
 }
 
 int main(int argc, char **argv) {
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     Var x, y;
     Func f, g, h;
 

test/correctness/fit_function.cpp

@@ -7,15 +7,6 @@
 using namespace Halide;
 
 int main(int argc, char **argv) {
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     // Fit an odd polynomial to sin from 0 to pi/2 using Halide's derivative support
     ImageParam coeffs(Float(64), 1);
     Param<double> learning_rate;

test/correctness/interleave_rgb.cpp

@@ -103,16 +103,6 @@ bool test_deinterleave(int x_stride) {
 }
 
 int main(int argc, char **argv) {
-    // LLVM 20 is missing llvm.vector.deinterleave4 for SVE and LLVM 21
-    // asserts (getFixedValue on scalable TypeSize). Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM %d has known SVE backend bugs for this test.\n",
-               Internal::get_llvm_version());
-        return 0;
-    }
-
     for (int x_stride : {3, 4}) {
         if (!test_interleave<uint8_t>(x_stride)) return 1;
         if (!test_interleave<uint16_t>(x_stride)) return 1;

test/correctness/logical.cpp

@@ -12,15 +12,6 @@ Expr u16(Expr a) {
 }
 
 int main(int argc, char **argv) {
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     Buffer<uint8_t> input(128, 64);
 
     for (int y = 0; y < input.height(); y++) {

test/correctness/predicated_store_load.cpp

@@ -487,15 +487,6 @@ int predicated_atomic_store_test(const Target &t) {
 int main(int argc, char **argv) {
     Target t = get_jit_target_from_environment();
 
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        t.has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     printf("Running vectorized dense load test\n");
     if (predicated_tail_test(t) != 0) {
         return 1;

test/correctness/stage_strided_loads.cpp

@@ -56,16 +56,6 @@ class CheckForStridedLoads : public IRMutator {
 } checker;
 
 int main(int argc, char **argv) {
-    // LLVM 20 is missing llvm.vector.deinterleave4 for SVE and LLVM 21
-    // asserts (getFixedValue on scalable TypeSize). Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM %d has known SVE backend bugs for this test.\n",
-               Internal::get_llvm_version());
-        return 0;
-    }
-
     ImageParam buf(Float(32), 1, "buf");
 
     {

test/correctness/truncated_pyramid.cpp

@@ -6,15 +6,6 @@ using std::pair;
 using std::vector;
 
 int main(int argc, char **argv) {
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     Func input;
     Var x, y;
     input(x, y) = random_float();

test/correctness/vector_reductions.cpp

@@ -160,16 +160,6 @@ void add_tasks(const Target &target, std::vector<Task> &tasks) {
 int main(int argc, char **argv) {
     Target target = get_jit_target_from_environment();
 
-    // LLVM 20 hangs and LLVM 21 asserts (getFixedValue on scalable TypeSize)
-    // in the AArch64 backend for SVE. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        target.has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM %d has known SVE backend bugs for this test.\n",
-               Internal::get_llvm_version());
-        return 0;
-    }
-
     // TODO(https://github.com/halide/Halide/issues/8985): LLVM's JIT emits
     // misaligned jump tables on arm-32 with arm_fp16, causing SIGILL.
     if (target.arch == Target::ARM && target.bits == 32 &&

test/correctness/vectorize_nested.cpp

@@ -277,15 +277,6 @@ int vectorize_inner_of_scalarization() {
 }
 
 int main(int argc, char **argv) {
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        get_jit_target_from_environment().has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     if (vectorize_2d_round_up()) {
         printf("vectorize_2d_round_up failed\n");
         return 1;

test/performance/const_division.cpp

@@ -191,15 +191,6 @@ int main(int argc, char **argv) {
         return 0;
     }
 
-    // LLVM 21 calls getFixedValue() on scalable TypeSize objects in the
-    // AArch64 backend, triggering an assertion. Fixed in LLVM 22 by:
-    // https://github.com/llvm/llvm-project/commit/d1500d12be60 (PR #169764)
-    if (Internal::get_llvm_version() < 220 &&
-        target.has_feature(Target::SVE2)) {
-        printf("[SKIP] LLVM 21 has known getFixedValue() assertion failures on SVE scalable types.\n");
-        return 0;
-    }
-
     int seed = argc > 1 ? atoi(argv[1]) : time(nullptr);
     rng.seed(seed);
     std::cout << "const_division test seed: " << seed << std::endl;