align src for IrInstructionArrayToVector

[mikdusan]

closes #2942

reduction.zig - executable segfaults

pub fn main() void {
    var foo: f32 = 3.14;
    var arr = [4]f32 { foo, 1.5, 0.0, 0.0 };
    var vec: @Vector(4, f32) = arr;
}

• what follows is llvm-ir comparison of broken vs. fixed
• hint: last load operation uses incorrect alignment 16

llvm-ir diff

--- broken.ll	2019-07-24 13:13:00.467787038 -0400
+++ fixed.ll	2019-07-24 13:13:04.055156465 -0400
@@ -16,7 +16,7 @@
   store float 0.000000e+00, float* %4, align 4, !dbg !11376
   call void @llvm.dbg.declare(metadata [4 x float]* %arr, metadata !11368, metadata !DIExpression()), !dbg !11377
   %5 = bitcast [4 x float]* %arr to <4 x float>*, !dbg !11378
-  %6 = load <4 x float>, <4 x float>* %5, align 16, !dbg !11378
+  %6 = load <4 x float>, <4 x float>* %5, align 4, !dbg !11378
   store <4 x float> %6, <4 x float>* %vec, align 16, !dbg !11379
   call void @llvm.dbg.declare(metadata <4 x float>* %vec, metadata !11370, metadata !DIExpression()), !dbg !11379
   ret void, !dbg !11380

broken llvm-ir

define internal fastcc void @main.0() unnamed_addr #0 !dbg !11362 {
Entry:
  %foo = alloca float, align 4
  %arr = alloca [4 x float], align 4
  %vec = alloca <4 x float>, align 16
  store float 0x40091EB860000000, float* %foo, align 4, !dbg !11372
  call void @llvm.dbg.declare(metadata float* %foo, metadata !11365, metadata !DIExpression()), !dbg !11372
  %0 = getelementptr inbounds [4 x float], [4 x float]* %arr, i64 0, i64 0, !dbg !11373
  %1 = load float, float* %foo, align 4, !dbg !11373
  store float %1, float* %0, align 4, !dbg !11373
  %2 = getelementptr inbounds [4 x float], [4 x float]* %arr, i64 0, i64 1, !dbg !11374
  %3 = getelementptr inbounds [4 x float], [4 x float]* %arr, i64 0, i64 2, !dbg !11375
  %4 = getelementptr inbounds [4 x float], [4 x float]* %arr, i64 0, i64 3, !dbg !11376
  store float 1.500000e+00, float* %2, align 4, !dbg !11374
  store float 0.000000e+00, float* %3, align 4, !dbg !11375
  store float 0.000000e+00, float* %4, align 4, !dbg !11376
  call void @llvm.dbg.declare(metadata [4 x float]* %arr, metadata !11368, metadata !DIExpression()), !dbg !11377
  %5 = bitcast [4 x float]* %arr to <4 x float>*, !dbg !11378
  %6 = load <4 x float>, <4 x float>* %5, align 16, !dbg !11378
  store <4 x float> %6, <4 x float>* %vec, align 16, !dbg !11379
  call void @llvm.dbg.declare(metadata <4 x float>* %vec, metadata !11370, metadata !DIExpression()), !dbg !11379
  ret void, !dbg !11380
}

fixed llvm-ir

define internal fastcc void @main.0() unnamed_addr #0 !dbg !11362 {
Entry:
  %foo = alloca float, align 4
  %arr = alloca [4 x float], align 4
  %vec = alloca <4 x float>, align 16
  store float 0x40091EB860000000, float* %foo, align 4, !dbg !11372
  call void @llvm.dbg.declare(metadata float* %foo, metadata !11365, metadata !DIExpression()), !dbg !11372
  %0 = getelementptr inbounds [4 x float], [4 x float]* %arr, i64 0, i64 0, !dbg !11373
  %1 = load float, float* %foo, align 4, !dbg !11373
  store float %1, float* %0, align 4, !dbg !11373
  %2 = getelementptr inbounds [4 x float], [4 x float]* %arr, i64 0, i64 1, !dbg !11374
  %3 = getelementptr inbounds [4 x float], [4 x float]* %arr, i64 0, i64 2, !dbg !11375
  %4 = getelementptr inbounds [4 x float], [4 x float]* %arr, i64 0, i64 3, !dbg !11376
  store float 1.500000e+00, float* %2, align 4, !dbg !11374
  store float 0.000000e+00, float* %3, align 4, !dbg !11375
  store float 0.000000e+00, float* %4, align 4, !dbg !11376
  call void @llvm.dbg.declare(metadata [4 x float]* %arr, metadata !11368, metadata !DIExpression()), !dbg !11377
  %5 = bitcast [4 x float]* %arr to <4 x float>*, !dbg !11378
  %6 = load <4 x float>, <4 x float>* %5, align 4, !dbg !11378
  store <4 x float> %6, <4 x float>* %vec, align 16, !dbg !11379
  call void @llvm.dbg.declare(metadata <4 x float>* %vec, metadata !11370, metadata !DIExpression()), !dbg !11379
  ret void, !dbg !11380
}

[andrewrk]

Thanks! Test added in 9e11f67