[PPC] Properly update register save area offsets

The variables MinGPR/MinG8R were not updated properly when resetting the
offsets, which in the included testcase lead to saving the CR register
in the same location as R30.

This fixes another issue reported in PR26519.

Differential Revision: https://reviews.llvm.org/D33017


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303257 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 171 insertions, 9 deletions

diff --git a/lib/Target/PowerPC/PPCFrameLowering.cpp b/lib/Target/PowerPC/PPCFrameLowering.cpp
index 40bfe3a449f..57a1d373c88 100644
--- a/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -1765,31 +1765,36 @@ void PPCFrameLowering::processFunctionBeforeFrameFinalized(MachineFunction &MF,
   // Check whether the frame pointer register is allocated. If so, make sure it
   // is spilled to the correct offset.
   if (needsFP(MF)) {
-    HasGPSaveArea = true;
-
     int FI = PFI->getFramePointerSaveIndex();
     assert(FI && "No Frame Pointer Save Slot!");
-
     MFI.setObjectOffset(FI, LowerBound + MFI.getObjectOffset(FI));
+    // FP is R31/X31, so no need to update MinGPR/MinG8R.
+    HasGPSaveArea = true;
   }
 
   if (PFI->usesPICBase()) {
-    HasGPSaveArea = true;
-
     int FI = PFI->getPICBasePointerSaveIndex();
     assert(FI && "No PIC Base Pointer Save Slot!");
-
     MFI.setObjectOffset(FI, LowerBound + MFI.getObjectOffset(FI));
+
+    MinGPR = std::min<unsigned>(MinGPR, PPC::R30);
+    HasGPSaveArea = true;
   }
 
   const PPCRegisterInfo *RegInfo = Subtarget.getRegisterInfo();
   if (RegInfo->hasBasePointer(MF)) {
-    HasGPSaveArea = true;
-
     int FI = PFI->getBasePointerSaveIndex();
     assert(FI && "No Base Pointer Save Slot!");
-
     MFI.setObjectOffset(FI, LowerBound + MFI.getObjectOffset(FI));
+
+    unsigned BP = RegInfo->getBaseRegister(MF);
+    if (PPC::G8RCRegClass.contains(BP)) {
+      MinG8R = std::min<unsigned>(MinG8R, BP);
+      HasG8SaveArea = true;
+    } else if (PPC::GPRCRegClass.contains(BP)) {
+      MinGPR = std::min<unsigned>(MinGPR, BP);
+      HasGPSaveArea = true;
+    }
   }
 
   // General register save area starts right below the Floating-point
diff --git a/test/CodeGen/PowerPC/save-bp.ll b/test/CodeGen/PowerPC/save-bp.ll
new file mode 100644
index 00000000000..1c7e19a1d5c
--- /dev/null
+++ b/test/CodeGen/PowerPC/save-bp.ll
@@ -0,0 +1,54 @@
+; RUN: llc -march=ppc64 -ppc-always-use-base-pointer < %s | FileCheck %s --check-prefix CHECK --check-prefix PPC64
+; RUN: llc -march=ppc32 -ppc-always-use-base-pointer < %s | FileCheck %s --check-prefix CHECK --check-prefix PPC32
+; RUN: llc -march=ppc32 -ppc-always-use-base-pointer -relocation-model pic < %s | FileCheck %s --check-prefix CHECK --check-prefix PPC32PIC
+
+; CHECK-LABEL: fred:
+
+; Check for saving/restoring frame pointer (X31) and base pointer (X30)
+; on ppc64:
+; PPC64: std 31, -8(1)
+; PPC64: std 30, -16(1)
+; PPC64: ld 31, -8(1)
+; PPC64: ld 30, -16(1)
+
+; Check for saving/restoring frame pointer (R31) and base pointer (R30)
+; on ppc32:
+; PPC32: stwux 1, 1, 0
+; PPC32; addic 0, 0, -4
+; PPC32: stwx 31, 0, 0
+; PPC32: addic 0, 0, -4
+; PPC32: stwx 30, 0, 0
+; The restore sequence:
+; PPC32: lwz 31, 0(1)
+; PPC32: addic 30, 0, 8
+; PPC32: lwz 0, -4(31)
+; PPC32: lwz 30, -8(31)
+; PPC32: mr 1, 31
+; PPC32: mr 31, 0
+
+; Check for saving/restoring frame pointer (R31) and base pointer (R29)
+; on ppc32/pic. This is mostly the same as without pic, except that base
+; pointer is in R29.
+; PPC32PIC: stwux 1, 1, 0
+; PPC32PIC; addic 0, 0, -4
+; PPC32PIC: stwx 31, 0, 0
+; PPC32PIC: addic 0, 0, -8
+; PPC32PIC: stwx 29, 0, 0
+; The restore sequence:
+; PPC32PIC: lwz 31, 0(1)
+; PPC32PIC: addic 29, 0, 12
+; PPC32PIC: lwz 0, -4(31)
+; PPC32PIC: lwz 29, -12(31)
+; PPC32PIC: mr 1, 31
+; PPC32PIC: mr 31, 0
+
+
+target datalayout = "E-m:e-p:32:32-i64:64-n32"
+target triple = "powerpc-unknown-freebsd"
+
+define i64 @fred() local_unnamed_addr #0 {
+entry:
+  ret i64 0
+}
+
+attributes #0 = { norecurse readnone nounwind sspstrong "no-frame-pointer-elim"="true" "target-cpu"="ppc" }
diff --git a/test/CodeGen/PowerPC/save-cr-ppc32svr4.ll b/test/CodeGen/PowerPC/save-cr-ppc32svr4.ll
new file mode 100644
index 00000000000..9fabca18605
--- /dev/null
+++ b/test/CodeGen/PowerPC/save-cr-ppc32svr4.ll
@@ -0,0 +1,46 @@
+; RUN: llc -march=ppc32 -relocation-model pic < %s | FileCheck %s
+;
+; Make sure that the CR register is saved correctly on PPC32/SVR4.
+
+; CHECK-LABEL: fred:
+; CHECK: stwu 1, -32(1)
+; CHECK: stw 31, 28(1)
+; CHECK: mr 31, 1
+; CHECK: stw 30, 24(1)
+; CHECK: mfcr [[CR:[0-9]+]]
+; CHECK: stw [[CR]], 20(31)
+
+target datalayout = "E-m:e-p:32:32-i64:64-n32"
+target triple = "powerpc-unknown-freebsd"
+
+; Function Attrs: norecurse nounwind readnone sspstrong
+define i64 @fred(double %a0) local_unnamed_addr #0 {
+b1:
+  %v2 = fcmp olt double %a0, 0x43E0000000000000
+  br i1 %v2, label %b3, label %b7
+
+b3:                                               ; preds = %b1
+  %v4 = fcmp olt double %a0, 0xC3E0000000000000
+  %v5 = fptosi double %a0 to i64
+  %v6 = select i1 %v4, i64 -9223372036854775808, i64 %v5
+  br label %b14
+
+b7:                                               ; preds = %b1
+  %v8 = fcmp olt double %a0, 0x43F0000000000000
+  br i1 %v8, label %b9, label %b11
+
+b9:                                               ; preds = %b7
+  %v10 = fptoui double %a0 to i64
+  br label %b14
+
+b11:                                              ; preds = %b7
+  %v12 = fcmp ogt double %a0, 0.000000e+00
+  %v13 = sext i1 %v12 to i64
+  br label %b14
+
+b14:                                              ; preds = %b11, %b9, %b3
+  %v15 = phi i64 [ %v6, %b3 ], [ %v10, %b9 ], [ %v13, %b11 ]
+  ret i64 %v15
+}
+
+attributes #0 = { norecurse nounwind readnone sspstrong "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "stack-protector-buffer-size"="8" "target-cpu"="ppc" }
diff --git a/test/CodeGen/PowerPC/save-crbp-ppc32svr4.ll b/test/CodeGen/PowerPC/save-crbp-ppc32svr4.ll
new file mode 100644
index 00000000000..b7b3c1ada96
--- /dev/null
+++ b/test/CodeGen/PowerPC/save-crbp-ppc32svr4.ll
@@ -0,0 +1,57 @@
+; RUN: llc -march=ppc32 -relocation-model pic < %s | FileCheck %s
+
+; CHECK-LABEL: fred
+; CHECK: stwux 1, 1, 0
+; Save R31..R29 via R0:
+; CHECK: addic 0, 0, -4
+; CHECK: stwx 31, 0, 0
+; CHECK: addic 0, 0, -4
+; CHECK: stwx 30, 0, 0
+; CHECK: addic 0, 0, -4
+; CHECK: stwx 29, 0, 0
+; Set R29 back to the value of R0 from before the updates:
+; CHECK: addic 29, 0, 12
+; Save CR through R12 using R29 as the stack pointer (aligned base pointer).
+; CHECK: mfcr 12
+; CHECK: stw 28, -16(29)
+; CHECK: stw 12, -20(29)
+
+target datalayout = "E-m:e-p:32:32-i64:64-n32"
+target triple = "powerpc-unknown-freebsd"
+
+; Function Attrs: norecurse readnone sspstrong
+define i64 @fred(double %a0) local_unnamed_addr #0 {
+b1:
+  %v2 = alloca i64, align 128
+  store i64 0, i64* %v2
+  %v3 = fcmp olt double %a0, 0x43E0000000000000
+  br i1 %v3, label %b4, label %b8
+
+b4:                                               ; preds = %b1
+  %v5 = fcmp olt double %a0, 0xC3E0000000000000
+  %v6 = fptosi double %a0 to i64
+  store i64 %v6, i64* %v2
+  %v7 = select i1 %v5, i64 -9223372036854775808, i64 %v6
+  br label %b15
+
+b8:                                               ; preds = %b1
+  %v9 = fcmp olt double %a0, 0x43F0000000000000
+  br i1 %v9, label %b10, label %b12
+
+b10:                                              ; preds = %b8
+  %v11 = fptoui double %a0 to i64
+  br label %b15
+
+b12:                                              ; preds = %b8
+  %v13 = fcmp ogt double %a0, 0.000000e+00
+  %v14 = sext i1 %v13 to i64
+  br label %b15
+
+b15:                                              ; preds = %b12, %b10, %b4
+  %v16 = phi i64 [ %v7, %b4 ], [ %v11, %b10 ], [ %v14, %b12 ]
+  %v17 = load i64, i64* %v2
+  %v18 = add i64 %v17, %v16
+  ret i64 %v18
+}
+
+attributes #0 = { norecurse readnone sspstrong "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "stack-protector-buffer-size"="8" "target-cpu"="ppc" }