[llvm] 9d90f8b - ARM: Remove override of shouldRewriteCopySrc (#125219)

[via llvm-commits]

Author: Matt Arsenault
Date: 2025-05-05T19:57:04+02:00
New Revision: 9d90f8ba7113fd9c7b2662682ad94b744ed2b78c

URL: https://github.com/llvm/llvm-project/commit/9d90f8ba7113fd9c7b2662682ad94b744ed2b78c
DIFF: https://github.com/llvm/llvm-project/commit/9d90f8ba7113fd9c7b2662682ad94b744ed2b78c.diff

LOG: ARM: Remove override of shouldRewriteCopySrc (#125219)

All of the overrides of shouldRewriteCopySrc appear to be hacks
for bugs in the base implementation, so I'm trying to delete
all of the overrides. I was expecting this to find an example
issue like the x86 version, but no tests change with this.

Added: 
    

Modified: 
    llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp
    llvm/lib/Target/ARM/ARMBaseRegisterInfo.h
    llvm/test/CodeGen/ARM/shouldRewriteCopySrc.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index bc20daf0cfbbc..82941b5bcd4c7 100644
--- a/llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -961,17 +961,3 @@ bool ARMBaseRegisterInfo::shouldCoalesce(MachineInstr *MI,
   }
   return false;
 }
-
-bool ARMBaseRegisterInfo::shouldRewriteCopySrc(const TargetRegisterClass *DefRC,
-                                               unsigned DefSubReg,
-                                               const TargetRegisterClass *SrcRC,
-                                               unsigned SrcSubReg) const {
-  // We can't extract an SPR from an arbitary DPR (as opposed to a DPR_VFP2).
-  if (DefRC == &ARM::SPRRegClass && DefSubReg == 0 &&
-      SrcRC == &ARM::DPRRegClass &&
-      (SrcSubReg == ARM::ssub_0 || SrcSubReg == ARM::ssub_1))
-    return false;
-
-  return TargetRegisterInfo::shouldRewriteCopySrc(DefRC, DefSubReg,
-                                                  SrcRC, SrcSubReg);
-}

diff  --git a/llvm/lib/Target/ARM/ARMBaseRegisterInfo.h b/llvm/lib/Target/ARM/ARMBaseRegisterInfo.h
index 69e10ac2a54d2..71fe2d2b70828 100644
--- a/llvm/lib/Target/ARM/ARMBaseRegisterInfo.h
+++ b/llvm/lib/Target/ARM/ARMBaseRegisterInfo.h
@@ -159,11 +159,6 @@ class ARMBaseRegisterInfo : public ARMGenRegisterInfo {
                       const TargetRegisterClass *NewRC,
                       LiveIntervals &LIS) const override;
 
-  bool shouldRewriteCopySrc(const TargetRegisterClass *DefRC,
-                            unsigned DefSubReg,
-                            const TargetRegisterClass *SrcRC,
-                            unsigned SrcSubReg) const override;
-
   int getSEHRegNum(unsigned i) const { return getEncodingValue(i); }
 };
 

diff  --git a/llvm/test/CodeGen/ARM/shouldRewriteCopySrc.ll b/llvm/test/CodeGen/ARM/shouldRewriteCopySrc.ll
index e653aaa316fed..2bf8f29eccb40 100644
--- a/llvm/test/CodeGen/ARM/shouldRewriteCopySrc.ll
+++ b/llvm/test/CodeGen/ARM/shouldRewriteCopySrc.ll
@@ -12,8 +12,8 @@ define float @shouldRewriteCopySrc(double %arg) #0 {
 ; CHECK-NEXT:    @APP
 ; CHECK-NEXT:    nop
 ; CHECK-NEXT:    @NO_APP
-; CHECK-NEXT:    vmov r0, r1, d16
-; CHECK-NEXT:    vmov s0, r0
+; CHECK-NEXT:    vmov.f64 d0, d16
+; CHECK-NEXT:    @ kill: def $s0 killed $s0 killed $d0
 ; CHECK-NEXT:    vpop {d8, d9, d10, d11, d12, d13, d14, d15}
 ; CHECK-NEXT:    bx lr
 bb: