Fix alignment in AArch64InstructionSelector::emitConstantPoolEntry()

The code was using the alignment of a pointer to the value, not the
alignment of the constant itself.

Maybe we got away with it so far because the pointer alignment is
fairly high, but we did end up under-aligning <16 x i8> vectors,
which was caught in the Chromium build after lld stopped over-aligning
the .rodata.cst16 section in r356428. (See crbug.com/953815)

Differential revision: https://reviews.llvm.org/D61124

llvm-svn: 359287

diff --git a/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp b/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
index 51501c1a9c78b5a747269d8330ed99fb5c143dd3..8a3310bf4e31ba1b4bfc4e687962b4d6e83f9f9c 100644 (file)
--- a/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
@@ -2572,7 +2572,7 @@ void AArch64InstructionSelector::collectShuffleMaskIndices(
 unsigned
 AArch64InstructionSelector::emitConstantPoolEntry(Constant *CPVal,
                                                   MachineFunction &MF) const {
-  Type *CPTy = CPVal->getType()->getPointerTo();
+  Type *CPTy = CPVal->getType();
   unsigned Align = MF.getDataLayout().getPrefTypeAlignment(CPTy);
   if (Align == 0)
     Align = MF.getDataLayout().getTypeAllocSize(CPTy);

diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/select-shuffle-vector.mir b/llvm/test/CodeGen/AArch64/GlobalISel/select-shuffle-vector.mir
index 008c43fad63e35940421ffda54fd2507d8574dc5..20f3c38005df5b85967efbc18e6f7f09a458b18c 100644 (file)
--- a/llvm/test/CodeGen/AArch64/GlobalISel/select-shuffle-vector.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/select-shuffle-vector.mir
@@ -82,7 +82,7 @@ body:             |
     ; CHECK-LABEL: name: shuffle_v4i32
     ; CHECK: constants:
     ; CHECK: value:           '<16 x i8> <i8 0, i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 12, i8 13, i8 14, i8 15, i8 0, i8 1, i8 2, i8 3>'
-    ; CHECK: alignment:       8
+    ; CHECK: alignment:       16
     ; CHECK: isTargetSpecific: false
     ; CHECK: liveins: $q0, $q1
     ; CHECK: [[COPY:%[0-9]+]]:fpr128 = COPY $q0
@@ -117,7 +117,7 @@ body:             |
     ; CHECK-LABEL: name: shuffle_tbl_v4i32
     ; CHECK: constants:
     ; CHECK: value:           '<16 x i8> <i8 20, i8 21, i8 22, i8 23, i8 28, i8 29, i8 30, i8 31, i8 4, i8 5, i8 6, i8 7, i8 0, i8 1, i8 2, i8 3>'
-    ; CHECK: alignment:       8
+    ; CHECK: alignment:       16
     ; CHECK: isTargetSpecific: false
     ; CHECK: liveins: $q0, $q1
     ; CHECK: [[COPY:%[0-9]+]]:fpr128 = COPY $q0
@@ -153,7 +153,7 @@ body:             |
     ; CHECK-LABEL: name: shuffle_v2i64
     ; CHECK: constants:
     ; CHECK: value:           '<16 x i8> <i8 0, i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 0, i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7>'
-    ; CHECK: alignment:       8
+    ; CHECK: alignment:       16
     ; CHECK: isTargetSpecific: false
     ; CHECK: liveins: $q0, $q1
     ; CHECK: [[COPY:%[0-9]+]]:fpr128 = COPY $q0