[llvm] b0f11df - [RISCV] Add call preserved regmask to tail calls. (#122181)

[via llvm-commits]

Author: Craig Topper
Date: 2025-01-08T16:19:31-08:00
New Revision: b0f11dfc7506dd33ad5b43be9faba919b70d1959

URL: https://github.com/llvm/llvm-project/commit/b0f11dfc7506dd33ad5b43be9faba919b70d1959
DIFF: https://github.com/llvm/llvm-project/commit/b0f11dfc7506dd33ad5b43be9faba919b70d1959.diff

LOG: [RISCV] Add call preserved regmask to tail calls. (#122181)

Every call should have regmask operand to indicate what registers are
preserved or clobbered by the call. VirtRegRewriter uses this to tell
MachineRegisterInfo what registers are clobbered by a function. If the
mask isn't present the registers potentially clobbered by a tail called
function aren't counted. I have checked ARM, AArch64, and X86 and they
all have a regmask operand on their tail calls.

I believe this fixes an issue I'm seeing with IPRA.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    llvm/test/CodeGen/RISCV/kcfi-isel-mir.ll
    llvm/test/CodeGen/RISCV/kcfi-mir.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 2eeca45ac414bd..6c58989b1afb4c 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -20273,13 +20273,11 @@ SDValue RISCVTargetLowering::LowerCall(CallLoweringInfo &CLI,
   for (auto &Reg : RegsToPass)
     Ops.push_back(DAG.getRegister(Reg.first, Reg.second.getValueType()));
 
-  if (!IsTailCall) {
-    // Add a register mask operand representing the call-preserved registers.
-    const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
-    const uint32_t *Mask = TRI->getCallPreservedMask(MF, CallConv);
-    assert(Mask && "Missing call preserved mask for calling convention");
-    Ops.push_back(DAG.getRegisterMask(Mask));
-  }
+  // Add a register mask operand representing the call-preserved registers.
+  const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
+  const uint32_t *Mask = TRI->getCallPreservedMask(MF, CallConv);
+  assert(Mask && "Missing call preserved mask for calling convention");
+  Ops.push_back(DAG.getRegisterMask(Mask));
 
   // Glue the call to the argument copies, if any.
   if (Glue.getNode())

diff  --git a/llvm/test/CodeGen/RISCV/kcfi-isel-mir.ll b/llvm/test/CodeGen/RISCV/kcfi-isel-mir.ll
index 4c47b5f741fa67..2c428cf4ac87c6 100644
--- a/llvm/test/CodeGen/RISCV/kcfi-isel-mir.ll
+++ b/llvm/test/CodeGen/RISCV/kcfi-isel-mir.ll
@@ -20,7 +20,7 @@ define void @f2(ptr noundef %x) #0 {
   ; CHECK-NEXT:   liveins: $x10
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT:   [[COPY:%[0-9]+]]:gprtc = COPY $x10
-  ; CHECK-NEXT:   PseudoTAILIndirect [[COPY]], implicit $x2, cfi-type 12345678
+  ; CHECK-NEXT:   PseudoTAILIndirect [[COPY]], csr_ilp32_lp64, implicit $x2, cfi-type 12345678
   tail call void %x() [ "kcfi"(i32 12345678) ]
   ret void
 }

diff  --git a/llvm/test/CodeGen/RISCV/kcfi-mir.ll b/llvm/test/CodeGen/RISCV/kcfi-mir.ll
index f9f383a35358c2..0c0d39a8bf87d3 100644
--- a/llvm/test/CodeGen/RISCV/kcfi-mir.ll
+++ b/llvm/test/CodeGen/RISCV/kcfi-mir.ll
@@ -30,7 +30,7 @@ define void @f2(ptr noundef %x) #0 {
   ; CHECK-NEXT: {{  $}}
   ; CHECK-NEXT:   BUNDLE implicit-def $x6, implicit-def $x6_w, implicit-def $x6_h, implicit-def $x7, implicit-def $x7_w, implicit-def $x7_h, implicit-def $x28, implicit-def $x28_w, implicit-def $x28_h, implicit-def $x29, implicit-def $x29_w, implicit-def $x29_h, implicit-def $x30, implicit-def $x30_w, implicit-def $x30_h, implicit-def $x31, implicit-def $x31_w, implicit-def $x31_h, implicit killed $x10, implicit $x2 {
   ; CHECK-NEXT:     KCFI_CHECK $x10, 12345678, implicit-def $x6, implicit-def $x7, implicit-def $x28, implicit-def $x29, implicit-def $x30, implicit-def $x31
-  ; CHECK-NEXT:     PseudoTAILIndirect killed $x10, implicit $x2
+  ; CHECK-NEXT:     PseudoTAILIndirect killed $x10, csr_ilp32_lp64, implicit $x2
   ; CHECK-NEXT:   }
   tail call void %x() [ "kcfi"(i32 12345678) ]
   ret void