[llvm] [RISCV] Correct RISCVTTIImpl::getIntImmCostInst for Zba (PR #128174)

[Gergely Futo via llvm-commits]

https://github.com/futog created https://github.com/llvm/llvm-project/pull/128174

zext.w is only available on RV64.

>From dd2c1eb16718695b73f0613aa5e8bbe2f8488486 Mon Sep 17 00:00:00 2001
From: Gergely Futo <gergely.futo at hightec-rt.com>
Date: Fri, 21 Feb 2025 14:25:54 +0100
Subject: [PATCH] [RISCV] Correct RISCVTTIImpl::getIntImmCostInst for Zba

zext.w is only available on RV64.
---
 llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp  |  2 +-
 .../Transforms/ConstantHoisting/RISCV/immediates.ll | 13 ++++++++-----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
index 79e3b9ee09744..bf921dff7154d 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
@@ -207,7 +207,7 @@ InstructionCost RISCVTTIImpl::getIntImmCostInst(unsigned Opcode, unsigned Idx,
     if (Imm == UINT64_C(0xffff) && ST->hasStdExtZbb())
       return TTI::TCC_Free;
     // zext.w
-    if (Imm == UINT64_C(0xffffffff) && ST->hasStdExtZba())
+    if (ST->isRV64() && Imm == UINT64_C(0xffffffff) && ST->hasStdExtZba())
       return TTI::TCC_Free;
     // bclri
     if (ST->hasStdExtZbs() && (~Imm).isPowerOf2())
diff --git a/llvm/test/Transforms/ConstantHoisting/RISCV/immediates.ll b/llvm/test/Transforms/ConstantHoisting/RISCV/immediates.ll
index 329281e7dc301..41fa6dc15fa25 100644
--- a/llvm/test/Transforms/ConstantHoisting/RISCV/immediates.ll
+++ b/llvm/test/Transforms/ConstantHoisting/RISCV/immediates.ll
@@ -1,5 +1,5 @@
-; RUN: opt -mtriple=riscv32-unknown-elf -S -passes=consthoist < %s | FileCheck %s
-; RUN: opt -mtriple=riscv64-unknown-elf -S -passes=consthoist < %s | FileCheck %s
+; RUN: opt -mtriple=riscv32-unknown-elf -S -passes=consthoist < %s | FileCheck %s -check-prefixes=CHECK,RV32I
+; RUN: opt -mtriple=riscv64-unknown-elf -S -passes=consthoist < %s | FileCheck %s -check-prefixes=CHECK,RV64I
 
 ; Check that we don't hoist immediates with small values.
 define i64 @test1(i64 %a) nounwind {
@@ -64,10 +64,13 @@ define i64 @test7(i64 %a) nounwind {
   ret i64 %2
 }
 
-; Check that we don't hoist zext.w with Zba.
+; Check that we don't hoist zext.w with Zba on riscv64-unknown-elf.
 define i64 @test8(i64 %a) nounwind "target-features"="+zba" {
-; CHECK-LABEL: test8
-; CHECK: and i64 %a, 4294967295
+; RV32I-LABEL: test8
+; RVI32: %const = bitcast i64 4294967295 to i64
+
+; RV64I-LABEL: test8
+; RV64I: and i64 %a, 4294967295
   %1 = and i64 %a, 4294967295
   %2 = and i64 %1, 4294967295
   ret i64 %2