From 6f28b0bb0ab3323c1c5c375db56b35c4933837e4 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Amaury=20S=C3=A9chet?= <deadalnix@gmail.com>
Date: Thu, 18 May 2023 14:44:53 +0000
Subject: [PATCH] [NFC] Flatten the logic in
 RISCVTargetLowering::decomposeMulByConstant

---
 llvm/lib/Target/RISCV/RISCVISelLowering.cpp | 52 ++++++++++++++++-------------
 1 file changed, 28 insertions(+), 24 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 9d954c7..c823792 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -15891,31 +15891,35 @@ bool RISCVTargetLowering::decomposeMulByConstant(LLVMContext &Context, EVT VT,
   // Check integral scalar types.
   const bool HasExtMOrZmmul =
       Subtarget.hasStdExtM() || Subtarget.hasStdExtZmmul();
-  if (VT.isScalarInteger()) {
-    // Omit the optimization if the sub target has the M extension and the data
-    // size exceeds XLen.
-    if (HasExtMOrZmmul && VT.getSizeInBits() > Subtarget.getXLen())
-      return false;
-    if (auto *ConstNode = dyn_cast<ConstantSDNode>(C.getNode())) {
-      // Break the MUL to a SLLI and an ADD/SUB.
-      const APInt &Imm = ConstNode->getAPIntValue();
-      if ((Imm + 1).isPowerOf2() || (Imm - 1).isPowerOf2() ||
-          (1 - Imm).isPowerOf2() || (-1 - Imm).isPowerOf2())
-        return true;
-      // Optimize the MUL to (SH*ADD x, (SLLI x, bits)) if Imm is not simm12.
-      if (Subtarget.hasStdExtZba() && !Imm.isSignedIntN(12) &&
-          ((Imm - 2).isPowerOf2() || (Imm - 4).isPowerOf2() ||
-           (Imm - 8).isPowerOf2()))
+  if (!VT.isScalarInteger())
+    return false;
+  
+  // Omit the optimization if the sub target has the M extension and the data
+  // size exceeds XLen.
+  if (HasExtMOrZmmul && VT.getSizeInBits() > Subtarget.getXLen())
+    return false;
+
+  if (auto *ConstNode = dyn_cast<ConstantSDNode>(C.getNode())) {
+    // Break the MUL to a SLLI and an ADD/SUB.
+    const APInt &Imm = ConstNode->getAPIntValue();
+    if ((Imm + 1).isPowerOf2() || (Imm - 1).isPowerOf2() ||
+        (1 - Imm).isPowerOf2() || (-1 - Imm).isPowerOf2())
+      return true;
+
+    // Optimize the MUL to (SH*ADD x, (SLLI x, bits)) if Imm is not simm12.
+    if (Subtarget.hasStdExtZba() && !Imm.isSignedIntN(12) &&
+        ((Imm - 2).isPowerOf2() || (Imm - 4).isPowerOf2() ||
+         (Imm - 8).isPowerOf2()))
+      return true;
+
+    // Break the MUL to two SLLI instructions and an ADD/SUB, if Imm needs
+    // a pair of LUI/ADDI.
+    if (!Imm.isSignedIntN(12) && Imm.countr_zero() < 12 &&
+        ConstNode->hasOneUse()) {
+      APInt ImmS = Imm.ashr(Imm.countr_zero());
+      if ((ImmS + 1).isPowerOf2() || (ImmS - 1).isPowerOf2() ||
+          (1 - ImmS).isPowerOf2())
         return true;
-      // Break the MUL to two SLLI instructions and an ADD/SUB, if Imm needs
-      // a pair of LUI/ADDI.
-      if (!Imm.isSignedIntN(12) && Imm.countr_zero() < 12 &&
-          ConstNode->hasOneUse()) {
-        APInt ImmS = Imm.ashr(Imm.countr_zero());
-        if ((ImmS + 1).isPowerOf2() || (ImmS - 1).isPowerOf2() ||
-            (1 - ImmS).isPowerOf2())
-          return true;
-      }
     }
   }
 
-- 
2.7.4