[llvm] 042a656 - [PowerPC] Guard XSRSP in P8 for FastISel

[Jinsong Ji via llvm-commits]

Author: Jinsong Ji
Date: 2021-09-07T15:17:51Z
New Revision: 042a6564d3656b5268fe9e2e2dad8e9726467710

URL: https://github.com/llvm/llvm-project/commit/042a6564d3656b5268fe9e2e2dad8e9726467710
DIFF: https://github.com/llvm/llvm-project/commit/042a6564d3656b5268fe9e2e2dad8e9726467710.diff

LOG: [PowerPC] Guard XSRSP in P8 for FastISel

This is exposed by enabling FastIsel on 64bit AIX.
We are generating XSRSP regardless of the arch,
which may be wrong when -mcpu=pwr7.

The fix is to guard the generation in P8 only.

Reviewed By: qiucf

Differential Revision: https://reviews.llvm.org/D109365

Added: 
    

Modified: 
    llvm/lib/Target/PowerPC/PPCFastISel.cpp
    llvm/test/CodeGen/PowerPC/fast-isel-rsp.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/PowerPC/PPCFastISel.cpp b/llvm/lib/Target/PowerPC/PPCFastISel.cpp
index 9148a8cb15544..856569bc8a73b 100644
--- a/llvm/lib/Target/PowerPC/PPCFastISel.cpp
+++ b/llvm/lib/Target/PowerPC/PPCFastISel.cpp
@@ -987,15 +987,16 @@ bool PPCFastISel::SelectFPTrunc(const Instruction *I) {
   auto RC = MRI.getRegClass(SrcReg);
   if (Subtarget->hasSPE()) {
     DestReg = createResultReg(&PPC::GPRCRegClass);
-    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
-      TII.get(PPC::EFSCFD), DestReg)
-      .addReg(SrcReg);
-  } else if (isVSFRCRegClass(RC)) {
+    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(PPC::EFSCFD),
+            DestReg)
+        .addReg(SrcReg);
+  } else if (Subtarget->hasP8Vector() && isVSFRCRegClass(RC)) {
     DestReg = createResultReg(&PPC::VSSRCRegClass);
-    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
-      TII.get(PPC::XSRSP), DestReg)
-      .addReg(SrcReg);
+    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(PPC::XSRSP),
+            DestReg)
+        .addReg(SrcReg);
   } else {
+    SrcReg = copyRegToRegClass(&PPC::F8RCRegClass, SrcReg);
     DestReg = createResultReg(&PPC::F4RCRegClass);
     BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
       TII.get(PPC::FRSP), DestReg)

diff  --git a/llvm/test/CodeGen/PowerPC/fast-isel-rsp.ll b/llvm/test/CodeGen/PowerPC/fast-isel-rsp.ll
index 700e159ac830b..2e55aa30bf110 100644
--- a/llvm/test/CodeGen/PowerPC/fast-isel-rsp.ll
+++ b/llvm/test/CodeGen/PowerPC/fast-isel-rsp.ll
@@ -2,6 +2,10 @@
 ; RUN:   -verify-machineinstrs | FileCheck %s --check-prefix=GENERIC
 ; RUN: llc -mcpu=ppc -mtriple=powerpc64le-unknown-unknown -O0 < %s \
 ; RUN:   -verify-machineinstrs | FileCheck %s
+; RUN: llc -mcpu=pwr7 -mtriple=powerpc64-ibm-aix-xcoff -O0 < %s \
+; RUN:   -verify-machineinstrs | FileCheck %s
+
+
 
 define float @testRSP(double %x) {
 entry: