[llvm] c268a3f - DAG: Fix extract of load combine with mismatched vector element type

[Matt Arsenault via llvm-commits]

Author: Matt Arsenault
Date: 2025-02-06T22:56:56+07:00
New Revision: c268a3f0934c625238a1391f6da55c10fecda9de

URL: https://github.com/llvm/llvm-project/commit/c268a3f0934c625238a1391f6da55c10fecda9de
DIFF: https://github.com/llvm/llvm-project/commit/c268a3f0934c625238a1391f6da55c10fecda9de.diff

LOG: DAG: Fix extract of load combine with mismatched vector element type

Fix the case where the vector element type of the loaded extractelement
input does not match the result type of the extract.

This fixes a regression reported after
c55a7659b38946350315ac4a18d9805deb1f0a54

Added: 
    llvm/test/CodeGen/ARM/pr122670-regression.ll

Modified: 
    llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 8858c2012c70671..ef58da873c59c58 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -23188,7 +23188,7 @@ SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
     auto *VecLoad = dyn_cast<LoadSDNode>(VecOp);
     if (VecLoad && VecLoad->isSimple()) {
       if (SDValue Scalarized = TLI.scalarizeExtractedVectorLoad(
-              ExtVT, SDLoc(N), VecVT, Index, VecLoad, DAG)) {
+              ScalarVT, SDLoc(N), VecVT, Index, VecLoad, DAG)) {
         ++OpsNarrowed;
         return Scalarized;
       }

diff  --git a/llvm/test/CodeGen/ARM/pr122670-regression.ll b/llvm/test/CodeGen/ARM/pr122670-regression.ll
new file mode 100644
index 000000000000000..396024150e22235
--- /dev/null
+++ b/llvm/test/CodeGen/ARM/pr122670-regression.ll
@@ -0,0 +1,20 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=armv7-unknown-linux-gnueabihf < %s | FileCheck %s
+
+; Check for assertion when extractelement of load optimization
+; involves a result element type 
diff erent from the input vector
+; element type.
+
+define i8 @baz(ptr %ptr, i32 %arg) {
+; CHECK-LABEL: baz:
+; CHECK:       @ %bb.0: @ %bb
+; CHECK-NEXT:    add r1, r1, r1
+; CHECK-NEXT:    and r1, r1, #3
+; CHECK-NEXT:    ldr r0, [r0, r1, lsl #2]
+; CHECK-NEXT:    bx lr
+bb:
+  %load = load <2 x i64>, ptr %ptr, align 8
+  %extractelement = extractelement <2 x i64> %load, i32 %arg
+  %trunc = trunc i64 %extractelement to i8
+  ret i8 %trunc
+}