[llvm] 89e84de - [AArch64][GlobalISel] Fix fallbacks introduced for G_SITOFP in 8f283cafddfa8d6d01a94b48cdc5d25817569e91

[Amara Emerson via llvm-commits]

Author: Amara Emerson
Date: 2021-01-15T01:10:49-08:00
New Revision: 89e84dec1879417fb7eb96edaa55dac7eca204ab

URL: https://github.com/llvm/llvm-project/commit/89e84dec1879417fb7eb96edaa55dac7eca204ab
DIFF: https://github.com/llvm/llvm-project/commit/89e84dec1879417fb7eb96edaa55dac7eca204ab.diff

LOG: [AArch64][GlobalISel] Fix fallbacks introduced for G_SITOFP in 8f283cafddfa8d6d01a94b48cdc5d25817569e91

If we have an integer->fp convert that has differing sizes, e.g. s32 to s64,
then don't try to convert it to AArch64::G_SITOF since it won't select.

Added: 
    

Modified: 
    llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
    llvm/test/CodeGen/AArch64/GlobalISel/select-fp-casts.mir

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp b/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
index 5dcb9b2d00da..797f33ce2ab4 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
@@ -1947,8 +1947,11 @@ bool AArch64InstructionSelector::preISelLower(MachineInstr &I) {
     // Otherwise, it ends up matching an fpr/gpr variant and adding a cross-bank
     // copy.
     Register SrcReg = I.getOperand(1).getReg();
-    if (MRI.getType(SrcReg).isVector())
+    LLT SrcTy = MRI.getType(SrcReg);
+    LLT DstTy = MRI.getType(I.getOperand(0).getReg());
+    if (SrcTy.isVector() || SrcTy.getSizeInBits() != DstTy.getSizeInBits())
       return false;
+
     if (RBI.getRegBank(SrcReg, MRI, TRI)->getID() == AArch64::FPRRegBankID) {
       if (I.getOpcode() == TargetOpcode::G_SITOFP)
         I.setDesc(TII.get(AArch64::G_SITOF));

diff  --git a/llvm/test/CodeGen/AArch64/GlobalISel/select-fp-casts.mir b/llvm/test/CodeGen/AArch64/GlobalISel/select-fp-casts.mir
index aad71bd99f8f..4274f91dba49 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/select-fp-casts.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/select-fp-casts.mir
@@ -327,6 +327,29 @@ body:             |
     $d0 = COPY %1(s64)
 ...
 
+---
+name:            sitofp_s64_s32_fpr_both
+legalized:       true
+regBankSelected: true
+
+registers:
+  - { id: 0, class: fpr }
+  - { id: 1, class: fpr }
+
+body:             |
+  bb.0:
+    liveins: $s0
+
+    ; CHECK-LABEL: name: sitofp_s64_s32_fpr
+    ; CHECK: [[COPY:%[0-9]+]]:fpr32 = COPY $s0
+    ; CHECK: [[COPY2:%[0-9]+]]:gpr32 = COPY [[COPY]]
+    ; CHECK: [[SCVTFUWDri:%[0-9]+]]:fpr64 = SCVTFUWDri [[COPY2]]
+    ; CHECK: $d0 = COPY [[SCVTFUWDri]]
+    %0(s32) = COPY $s0
+    %1(s64) = G_SITOFP %0
+    $d0 = COPY %1(s64)
+...
+
 ---
 name:            sitofp_s64_s64_fpr
 legalized:       true