Apply the AdjustICmpImmAndPred optimization when it results in a one-instruction immediate materialization over a two-instruction materialization.

[resistor]

#76460

[llvmbot]

@llvm/pr-subscribers-llvm-globalisel

@llvm/pr-subscribers-backend-aarch64

Author: Owen Anderson (resistor)

Changes

#76460

---

Full diff: https://github.com/llvm/llvm-project/pull/83218.diff

2 Files Affected:

• (modified) llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp (+8-4)
• (added) llvm/test/CodeGen/AArch64/GlobalISel/icmp-cst.ll (+185)

diff --git a/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp b/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
index 9bc5815ae05371..96c97cb4706d55 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64PostLegalizerLowering.cpp
@@ -588,7 +588,8 @@ tryAdjustICmpImmAndPred(Register RHS, CmpInst::Predicate P,
   auto ValAndVReg = getIConstantVRegValWithLookThrough(RHS, MRI);
   if (!ValAndVReg)
     return std::nullopt;
-  uint64_t C = ValAndVReg->Value.getZExtValue();
+  uint64_t OriginalC = ValAndVReg->Value.getZExtValue();
+  uint64_t C = OriginalC;
   if (isLegalArithImmed(C))
     return std::nullopt;
 
@@ -658,9 +659,12 @@ tryAdjustICmpImmAndPred(Register RHS, CmpInst::Predicate P,
   // predicate if it is.
   if (Size == 32)
     C = static_cast<uint32_t>(C);
-  if (!isLegalArithImmed(C))
-    return std::nullopt;
-  return {{C, P}};
+  if (isLegalArithImmed(C))
+    return {{C, P}};
+  if (AArch64_AM::isLogicalImmediate(C, Size) &&
+      !AArch64_AM::isLogicalImmediate(OriginalC, Size))
+    return {{C, P}};
+  return std::nullopt;
 }
 
 /// Determine whether or not it is possible to update the RHS and predicate of
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/icmp-cst.ll b/llvm/test/CodeGen/AArch64/GlobalISel/icmp-cst.ll
new file mode 100644
index 00000000000000..e6b27943372a83
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/icmp-cst.ll
@@ -0,0 +1,185 @@
+; RUN: llc -mtriple=aarch64-linux-gnu -global-isel=1 < %s | FileCheck %s
+
+; CHECK-NOT: movk
+
+define dso_local noundef i1 @ule_11111111(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, 286331154
+  ret i1 %2
+}
+
+define dso_local noundef i1 @ule_22222222(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, 572662307
+  ret i1 %2
+}
+
+define dso_local noundef i1 @ule_33333333(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, 858993460
+  ret i1 %2
+}
+
+define dso_local noundef i1 @ule_44444444(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, 1145324613
+  ret i1 %2
+}
+
+define dso_local noundef i1 @ule_55555555(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, 1431655766
+  ret i1 %2
+}
+
+define dso_local noundef i1 @ule_66666666(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, 1717986919
+  ret i1 %2
+}
+
+define dso_local noundef i1 @ule_77777777(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, 2004318072
+  ret i1 %2
+}
+
+define dso_local noundef i1 @ule_88888888(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, -2004318071
+  ret i1 %2
+}
+
+define dso_local noundef i1 @ule_99999999(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, -1717986918
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_11111111(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, 286331152
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_22222222(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, 572662305
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_33333333(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, 858993458
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_44444444(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, 1145324611
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_55555555(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, 1431655764
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_66666666(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, 1717986917
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_77777777(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, 2004318070
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_88888888(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, -2004318073
+  ret i1 %2
+}
+
+define dso_local noundef i1 @uge_99999999(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, -1717986920
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_11111111(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp slt i32 %0, 286331154
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_22222222(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp slt i32 %0, 572662307
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_33333333(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp slt i32 %0, 858993460
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_44444444(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp slt i32 %0, 1145324613
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_55555555(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp slt i32 %0, 1431655766
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_66666666(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp slt i32 %0, 1717986919
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_77777777(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp slt i32 %0, 2004318072
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_88888888(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, -2004318071
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sle_99999999(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ult i32 %0, -1717986918
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_11111111(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp sgt i32 %0, 286331152
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_22222222(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp sgt i32 %0, 572662305
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_33333333(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp sgt i32 %0, 858993458
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_44444444(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp sgt i32 %0, 1145324611
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_55555555(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp sgt i32 %0, 1431655764
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_66666666(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp sgt i32 %0, 1717986917
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_77777777(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp sgt i32 %0, 2004318070
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_88888888(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, -2004318073
+  ret i1 %2
+}
+
+define dso_local noundef i1 @sge_99999999(i32 noundef %0) local_unnamed_addr #0 {
+  %2 = icmp ugt i32 %0, -1717986920
+  ret i1 %2
+}
+
+attributes #0 = { mustprogress nofree norecurse nosync nounwind willreturn memory(none) uwtable "frame-pointer"="non-leaf" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="generic" "target-features"="+fp-armv8,+neon,+outline-atomics,+v8a,-fmv" }
\ No newline at end of file

[davemgreen]

It would be a bit more code, but could this all use AArch64_IMM::expandMOVImm(Imm, BitSize, Insn); Insn.size() == 1? I believe that is what this is trying to achieve, and it would be more general to capture all the different ways for the immediate to be a single instruction.

[ornata]

ping on this comment? @resistor

[resistor]

I've long since lost the context on this one, but feel free to adopt it if you want.

[davemgreen]

It would be good if the title had [AArch64][GlobalISel] too, to keep in consistent with all the other commits. The title might be a bit long too for a standard git commit. Some of it might fit better as the message.