[SystemZ] Prevent Merging Bitcast with non-normal loads

Fixes PR32505.

Reviewers: uweigand, jonpa

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31609

llvm-svn: 299552

2 files changed, 23 insertions, 2 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
index 5078accbaf3..2db35eabe63 100644
--- a/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -2792,8 +2792,9 @@ SDValue SystemZTargetLowering::lowerBITCAST(SDValue Op,
   // but we need this case for bitcasts that are created during lowering
   // and which are then lowered themselves.
   if (auto *LoadN = dyn_cast<LoadSDNode>(In))
-    return DAG.getLoad(ResVT, DL, LoadN->getChain(), LoadN->getBasePtr(),
-                       LoadN->getMemOperand());
+    if (ISD::isNormalLoad(LoadN))
+      return DAG.getLoad(ResVT, DL, LoadN->getChain(), LoadN->getBasePtr(),
+                         LoadN->getMemOperand());
 
   if (InVT == MVT::i32 && ResVT == MVT::f32) {
     SDValue In64;
diff --git a/llvm/test/CodeGen/SystemZ/pr32505.ll b/llvm/test/CodeGen/SystemZ/pr32505.ll
new file mode 100644
index 00000000000..6abad022016
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/pr32505.ll
@@ -0,0 +1,20 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mcpu=zEC12 -o - %s | FileCheck %s
+
+target triple = "s390x-ibm-linux"
+
+define <2 x float> @pr32505(<2 x i8> * %a) {
+; CHECK-LABEL: pr32505:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    lbh %r0, 0(%r2)
+; CHECK-NEXT:    ldgr %f0, %r0
+; CHECK-NEXT:    lbh %r0, 1(%r2)
+; CHECK-NEXT:    ldgr %f2, %r0
+; CHECK-NEXT:    # kill: %F0S<def> %F0S<kill> %F0D<kill>
+; CHECK-NEXT:    # kill: %F2S<def> %F2S<kill> %F2D<kill>
+; CHECK-NEXT:    br %r14
+  %L17 = load <2 x i8>, <2 x i8>* %a
+  %Se21 = sext <2 x i8> %L17 to <2 x i32>
+  %BC = bitcast <2 x i32> %Se21 to <2 x float>
+  ret <2 x float> %BC
+}